A timing attack against mod_auth_digest in Apache HTTP Server 2.4.66 allows a bypass of Digest authentication by a remote attacker. Users are recommended to upgrade to version 2.4.67, which fixes this issue.

The remote SUSE Linux SLED15 / SLED_SAP15 / SLES15 / SLES_SAP15 host has packages installed that are affected by multiple vulnerabilities as referenced in the SUSE-SU-2026:2104-1 advisory.

    This update for apache2 fixes the following issues

    - CVE-2026-23918: http2: double free and possible RCE on early reset (bsc#1263957).
    - CVE-2026-24072: mod_rewrite elevation of privileges via ap_expr (bsc#1263935).
    - CVE-2026-28780: heap buffer overflow in `mod_proxy_ajp` via `ajp_msg_check_header()` (bsc#1264163).
    - CVE-2026-29168: allocation of resources without limits in `mod_md` via OCSP response (bsc#1264150).
    - CVE-2026-29169: NULL pointer dereference in `mod_dav_lock` allows server crash via malicious requests     (bsc#1263956).
    - CVE-2026-33006: `mod_auth_digest` timing attack allows bypass of Digest authentication (bsc#1263955).
    - CVE-2026-33007: NULL pointer dereference in `mod_authn_socache` allows unauthenticated remote user to     crash a child       processes (bsc#1263954).
    - CVE-2026-33523: HTTP response splitting forwarding malicious status line (bsc#1263953).
    - CVE-2026-33857: off-by-one OOB reads in AJP getter functions (bsc#1263952).
    - CVE-2026-34032: heap buffer overread in `mod_proxy_ajp` due to missing null-termination check     (bsc#1263951).
    - CVE-2026-34059: heap buffer overread and memory disclosure via `ajp_parse_data()` (bsc#1263950).

Tenable has extracted the preceding description block directly from the SUSE security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The remote SUSE Linux SLES15 / SLES_SAP15 host has packages installed that are affected by multiple vulnerabilities as referenced in the SUSE-SU-2026:2103-1 advisory.

    This update for apache2 fixes the following issues

    - CVE-2026-23918: http2: double free and possible RCE on early reset (bsc#1263957).
    - CVE-2026-24072: mod_rewrite elevation of privileges via ap_expr (bsc#1263935).
    - CVE-2026-28780: heap buffer overflow in `mod_proxy_ajp` via `ajp_msg_check_header()` (bsc#1264163).
    - CVE-2026-29168: allocation of resources without limits in `mod_md` via OCSP response (bsc#1264150).
    - CVE-2026-29169: NULL pointer dereference in `mod_dav_lock` allows server crash via malicious requests     (bsc#1263956).
    - CVE-2026-33006: `mod_auth_digest` timing attack allows bypass of Digest authentication (bsc#1263955).
    - CVE-2026-33007: NULL pointer dereference in `mod_authn_socache` allows unauthenticated remote user to     crash a child       processes (bsc#1263954).
    - CVE-2026-33523: HTTP response splitting forwarding malicious status line (bsc#1263953).
    - CVE-2026-33857: off-by-one OOB reads in AJP getter functions (bsc#1263952).
    - CVE-2026-34032: heap buffer overread in `mod_proxy_ajp` due to missing null-termination check     (bsc#1263951).
    - CVE-2026-34059: heap buffer overread and memory disclosure via `ajp_parse_data()` (bsc#1263950).

Tenable has extracted the preceding description block directly from the SUSE security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The version of httpd installed on the remote host is prior to 2.4.67-1. It is, therefore, affected by multiple vulnerabilities as referenced in the ALAS2-2026-3314 advisory.

    An escalation of privilege bug in various modules in Apache HTTP 2.4.66 and earlier allows local .htaccess     authors to read files with the privileges of the httpd user.

    Users are recommended to upgrade to version 2.4.67, which fixes this issue. (CVE-2026-24072)

    Heap-based Buffer Overflow vulnerability in mod_proxy_ajp of Apache HTTP Server.If mod_proxy_ajp connects     to a malicious AJP server this AJP server can send a malicious AJP message back to mod_proxy_ajp and cause     it to write 4 attacker controlled bytes after the end of a heap based buffer.

    This issue affects Apache HTTP Server: through 2.4.66.

    Users are recommended to upgrade to version 2.4.67, which fixes the issue. (CVE-2026-28780)

    Allocation of Resources Without Limits or Throttling vulnerability in Apache HTTP Server's  mod_md via     OCSP response data.

    This issue affects Apache HTTP Server: from 2.4.30 through 2.4.66.

    Users are recommended to upgrade to version 2.4.67, which fixes the issue. (CVE-2026-29168)

    A NULL pointer dereference in mod_dav_lock in Apache HTTP Server 2.4.66 and earlier may allow an attacker     to crash the server with a malicious request.mod_dav_lock is not used internally by mod_dav or mod_dav_fs.

    The only known use-case for mod_dav_lock was mod_dav_svn from Apache Subversion earlier than version     1.2.0.

    Users are recommended to upgrade to version 2.4.66, which fixes this issue, or remove mod_dav_lock.
    (CVE-2026-29169)

    A timing attack against mod_auth_digest in Apache HTTP Server 2.4.66 allows a bypass of Digest     authentication by a remote attacker.

    Users are recommended to upgrade to version 2.4.67, which fixes this issue. (CVE-2026-33006)

    A NULL pointer dereference in the mod_authn_socache in Apache HTTP Server 2.4.66 and earlier allows an     unauthenticated remote user to crash a child process in a caching forward proxy configuration.

    Users are recommended to upgrade to version 2.4.67, which fixes this issue. (CVE-2026-33007)

    HTTP response splitting vulnerability in multiple Apache HTTP Server modules with untrusted or compromised     backend servers.

    This issue affects Apache HTTP Server: from through 2.4.66.

    Users are recommended to upgrade to version 2.4.67, which fixes the issue. (CVE-2026-33523)

    Out-of-bounds Read vulnerability in mod_proxy_ajp of

    Apache HTTP Server.

    This issue affects Apache HTTP Server: through 2.4.66.

    Users are recommended to upgrade to version 2.4.67, which fixes the issue. (CVE-2026-33857)

    Improper Null Termination, Out-of-bounds Read vulnerability in Apache HTTP Server.

    This issue affects Apache HTTP Server: through 2.4.66.

    Users are recommended to upgrade to version 2.4.67, which fixes the issue. (CVE-2026-34032)

    Buffer Over-read vulnerability in Apache HTTP Server.

    This issue affects Apache HTTP Server: through 2.4.66.

    Users are recommended to upgrade to version 2.4.67, which fixes the issue. (CVE-2026-34059)

Tenable has extracted the preceding description block directly from the tested product security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

It is, therefore, affected by multiple vulnerabilities as referenced in the ALAS2023-2026-1720 advisory.

    An escalation of privilege bug in various modules in Apache HTTP 2.4.66 and earlier allows local .htaccess     authors to read files with the privileges of the httpd user.

    Users are recommended to upgrade to version 2.4.67, which fixes this issue. (CVE-2026-24072)

    Heap-based Buffer Overflow vulnerability in mod_proxy_ajp of Apache HTTP Server.If mod_proxy_ajp connects     to a malicious AJP server this AJP server can send a malicious AJP message back to mod_proxy_ajp and cause     it to write 4 attacker controlled bytes after the end of a heap based buffer.

    This issue affects Apache HTTP Server: through 2.4.66.

    Users are recommended to upgrade to version 2.4.67, which fixes the issue. (CVE-2026-28780)

    Allocation of Resources Without Limits or Throttling vulnerability in Apache HTTP Server's  mod_md via     OCSP response data.

    This issue affects Apache HTTP Server: from 2.4.30 through 2.4.66.

    Users are recommended to upgrade to version 2.4.67, which fixes the issue. (CVE-2026-29168)

    A NULL pointer dereference in mod_dav_lock in Apache HTTP Server 2.4.66 and earlier may allow an attacker     to crash the server with a malicious request.mod_dav_lock is not used internally by mod_dav or mod_dav_fs.

    The only known use-case for mod_dav_lock was mod_dav_svn from Apache Subversion earlier than version     1.2.0.

    Users are recommended to upgrade to version 2.4.66, which fixes this issue, or remove mod_dav_lock.
    (CVE-2026-29169)

    A timing attack against mod_auth_digest in Apache HTTP Server 2.4.66 allows a bypass of Digest     authentication by a remote attacker.

    Users are recommended to upgrade to version 2.4.67, which fixes this issue. (CVE-2026-33006)

    A NULL pointer dereference in the mod_authn_socache in Apache HTTP Server 2.4.66 and earlier allows an     unauthenticated remote user to crash a child process in a caching forward proxy configuration.

    Users are recommended to upgrade to version 2.4.67, which fixes this issue. (CVE-2026-33007)

    HTTP response splitting vulnerability in multiple Apache HTTP Server modules with untrusted or compromised     backend servers.

    This issue affects Apache HTTP Server: from through 2.4.66.

    Users are recommended to upgrade to version 2.4.67, which fixes the issue. (CVE-2026-33523)

    Out-of-bounds Read vulnerability in mod_proxy_ajp of

    Apache HTTP Server.

    This issue affects Apache HTTP Server: through 2.4.66.

    Users are recommended to upgrade to version 2.4.67, which fixes the issue. (CVE-2026-33857)

    Improper Null Termination, Out-of-bounds Read vulnerability in Apache HTTP Server.

    This issue affects Apache HTTP Server: through 2.4.66.

    Users are recommended to upgrade to version 2.4.67, which fixes the issue. (CVE-2026-34032)

    Buffer Over-read vulnerability in Apache HTTP Server.

    This issue affects Apache HTTP Server: through 2.4.66.

    Users are recommended to upgrade to version 2.4.67, which fixes the issue. (CVE-2026-34059)

Tenable has extracted the preceding description block directly from the tested product security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The remote Fedora 43 host has a package installed that is affected by multiple vulnerabilities as referenced in the FEDORA-2026-0c87f546f8 advisory.

    - new version 2.4.67



Tenable has extracted the preceding description block directly from the Fedora security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

According to its banner, the version of Apache running on the remote host is 2.4.x prior to 2.4.67. It is, therefore, affected by multiple vulnerabilities:

- A Double Free and possible Remote Code Execution vulnerability exists in Apache HTTP Server when using the HTTP/2 protocol. (CVE-2026-23918)

- Local .htaccess authors can read files with the privileges of the httpd user through an elevation of privileges via ap_expr in mod_rewrite. (CVE-2026-24072)

- A heap-based buffer overflow exists in mod_proxy_ajp via ajp_msg_check_header(). A malicious AJP server can send a malicious AJP message causing 4 attacker-controlled bytes to be written after the end of a heap buffer. (CVE-2026-28780)

- Unrestricted OCSP response data handling in mod_md allows allocation of resources without limits or throttling. (CVE-2026-29168)

- A NULL pointer dereference in mod_dav_lock may allow denial of service with malicious requests. (CVE-2026-29169)

- A timing attack against mod_auth_digest allows bypass of Digest authentication by a remote attacker. (CVE-2026-33006)

- A NULL pointer dereference in mod_authn_socache allows an unauthenticated remote user to crash a child process in a caching forward proxy configuration. (CVE-2026-33007)

- An HTTP response splitting vulnerability exists in multiple modules when untrusted or compromised backend servers forward malicious status lines. (CVE-2026-33523)

- An out-of-bounds read vulnerability exists in mod_proxy_ajp getter functions. (CVE-2026-33857)

- A heap buffer over-read due to missing null-termination check exists in ajp_msg_get_string() in mod_proxy_ajp. (CVE-2026-34032)

- A heap over-read and memory disclosure vulnerability exists in ajp_parse_data() in mod_proxy_ajp. (CVE-2026-34059)

Note that the scanner has not tested for these issues but has instead relied only on the application's self-reported version number.

The remote Debian 11 host has packages installed that are affected by multiple vulnerabilities as referenced in the dla-4571 advisory.

    - -------------------------------------------------------------------------     Debian LTS Advisory DLA-4571-1                debian-lts@lists.debian.org     https://www.debian.org/lts/security/                   Bastien Roucaris     May 08, 2026                                  https://wiki.debian.org/LTS
    - -------------------------------------------------------------------------

    Package        : apache2     Version        : 2.4.67-1~deb11u1     CVE ID         : CVE-2026-24072 CVE-2026-28780 CVE-2026-29168 CVE-2026-29169                      CVE-2026-33006 CVE-2026-33007 CVE-2026-33523 CVE-2026-33857                      CVE-2026-34032 CVE-2026-34059     Debian Bug     : 1135737

    Multiple vulnerabilities have been discovered in the Apache HTTP server,     which may result in remote code execution, privilege escalation, denial     of service or information disclosure.

    An erratum was issued because DLA??4571??1 incorrectly marked CVE??2026??28780     and CVE??2026??29168 as not fixed.

    These two vulnerabilities are in fact addressed in version 2.4.67??1~deb11u1,     which includes the required security fixes.

    Additionally, CVE??2026??23918 was marked as not affecting Bullseye, as the     vulnerable code is not present in any previously released Bullseye packages.
    However, the updated package includes the fix for this issue as well,     even though it does not impact this release.

    For Debian 11 bullseye, these problems have been fixed in version     2.4.67-1~deb11u1.

    We recommend that you upgrade your apache2 packages.

    For the detailed security status of apache2 please refer to     its security tracker page at:
    https://security-tracker.debian.org/tracker/apache2

    Further information about Debian LTS security advisories, how to apply     these updates to your system and frequently asked questions can be     found at: https://wiki.debian.org/LTS

Tenable has extracted the preceding description block directly from the Debian security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The remote Ubuntu 22.04 LTS / 24.04 LTS / 25.10 / 26.04 LTS host has packages installed that are affected by multiple vulnerabilities as referenced in the USN-8239-1 advisory.

    Bartlomiej Dmitruk and Stanislaw Strzalkowski discovered that Apache HTTP Server incorrectly handled     certain memory operations when using the HTTP/2 protocol. A remote attacker could use this issue to cause     Apache HTTP Server to crash, resulting in a denial of service, or possibly execute arbitrary code. This     issue only affected Ubuntu 26.04 LTS. (CVE-2026-23918)

    It was discovered that the Apache HTTP Server mod_rewrite module incorrectly handled certain privileges. A     local attacker could possibly use this issue to obtain sensitive information. (CVE-2026-24072)

    Andrew Lacambra, Elhanan Haenel, Tianshuo Han, and Tristan Madani discovered that the Apache HTTP Server     mod_proxy_ajp module incorrectly handled certain AJP server messages. An attacker in control of a backend     AJP server could use this issue to cause Apache HTTP Server to crash, resulting in a denial of service, or     possibly execute arbitrary code. (CVE-2026-28780)

    Pavel Kohout discovered that Apache HTTP Server did not properly limit resource allocation in mod_md when     processing OCSP response data. A remote attacker could possibly use this issue to cause a denial of     service. (CVE-2026-29168)

    Pavel Kohout discovered that the Apache HTTP Server incorrectly handled certain memory operations in     mod_dav_lock. A remote attacker could possibly use this issue to cause Apache HTTP Server to crash,     resulting in a denial of service. (CVE-2026-29169)

    Nitescu Lucian discovered that Apache HTTP Server had a timing attack vulnerability in mod_auth_digest. A     remote attacker could possibly use this issue to bypass Digest authentication. (CVE-2026-33006)

    Pavel Kohout and Arkadi Vainbrand discovered that Apache HTTP Server incorrectly handled certain memory     operations in mod_authn_socache. A remote attacker could possibly use this issue to cause Apache HTTP     Server to crash, resulting in a denial of service. (CVE-2026-33007)

    Haruki Oyama, Merih Mengisteab, and Dawit Jeong discovered that Apache HTTP Server had an HTTP response     splitting vulnerability in multiple modules when used with untrusted or compromised backend servers. An     attacker could possibly use this issue to inject arbitrary HTTP headers. (CVE-2026-33523)

    Elhanan Haenel discovered that Apache HTTP Server incorrectly handled certain memory operations in     mod_proxy_ajp. A remote attacker could possibly use this issue to cause Apache HTTP Server to crash,     resulting in a denial of service. (CVE-2026-33857)

    Tianshuo Han and Jrme Djouder discovered that Apache HTTP Server incorrectly handled certain string     operations in mod_proxy_ajp. A remote attacker could possibly use this issue to obtain sensitive     information. (CVE-2026-34032)

    Elhanan Haenel discovered that Apache HTTP Server incorrectly handled certain memory operations in     mod_proxy_ajp. A remote attacker could use this issue to cause Apache HTTP Server to crash, resulting in a     denial of service, or possibly obtain sensitive information. (CVE-2026-34059)

Tenable has extracted the preceding description block directly from the Ubuntu security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The remote Debian 12 / 13 host has packages installed that are affected by multiple vulnerabilities as referenced in the dsa-6248 advisory.

    - -------------------------------------------------------------------------     Debian Security Advisory DSA-6248-1                   security@debian.org     https://www.debian.org/security/                     Salvatore Bonaccorso     May 06, 2026                          https://www.debian.org/security/faq
    - -------------------------------------------------------------------------

    Package        : apache2     CVE ID         : CVE-2026-23918 CVE-2026-24072 CVE-2026-28780 CVE-2026-29168                      CVE-2026-29169 CVE-2026-33006 CVE-2026-33007 CVE-2026-33523                      CVE-2026-33857 CVE-2026-34032 CVE-2026-34059     Debian Bug     : 1135737

    Multiple vulnerabilities have been discovered in the Apache HTTP server,     which may result in remote code execution, privilege escalation, denial     of service or information disclosure.

    For the oldstable distribution (bookworm), these problems have been fixed     in version 2.4.67-1~deb12u2.

    For the stable distribution (trixie), these problems have been fixed in     version 2.4.67-1~deb13u2. The fix for CVE-2026-23918 was already     included in the Debian 13.4 point release update versioned     2.4.66-1~deb13u2 to address reported HTTP/2 regressions.

    We recommend that you upgrade your apache2 packages.

    For the detailed security status of apache2 please refer to its security     tracker page at:
    https://security-tracker.debian.org/tracker/apache2

    Further information about Debian Security Advisories, how to apply     these updates to your system and frequently asked questions can be     found at: https://www.debian.org/security/

    Mailing list: debian-security-announce@lists.debian.org

Tenable has extracted the preceding description block directly from the Debian security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The version of FreeBSD installed on the remote host is prior to tested version. It is, therefore, affected by multiple vulnerabilities as referenced in the 1ccc383b-486a-11f1-8b62-8447094a420f advisory.

    The Apache httpd project reports:
    mod_proxy_ajp: CVE-2026-34059, CVE-2026-34032, CVE-2026-33857, CVE-2026-28780     multiple modules: CVE-2026-33523     mod_authn_socache: CVE-2026-33007     mod_auth_digest: CVE-2026-33006     mod_dav_lock: mod_dav_lock     mod_md: CVE-2026-29168     mod_rewrite: CVE-2026-24072     mod_http2: CVE-2026-23918

Tenable has extracted the preceding description block directly from the FreeBSD security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available.

  - A timing attack against mod_auth_digest in Apache HTTP Server 2.4.66 allows a bypass of Digest     authentication by a remote attacker. Users are recommended to upgrade to version 2.4.67, which fixes this     issue. (CVE-2026-33006)

Note that Nessus relies on the presence of the package as reported by the vendor.

The version of httpd installed on the remote host is prior to 2.4.67. It is, therefore, affected by multiple vulnerabilities as referenced in the SSA:2026-124-01 advisory.

    New httpd packages are available for Slackware 15.0 and -current to fix security issues.

Tenable has extracted the preceding description block directly from the httpd security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The version of Apache httpd installed on the remote host is prior to 2.4.67. It is, therefore, affected by multiple vulnerabilities as referenced in the 2.4.67 advisory.

  - Heap-based Buffer Overflow vulnerability in mod_proxy_ajp of Apache HTTP Server. If mod_proxy_ajp connects     to a malicious AJP server this AJP server can send a malicious AJP message back to mod_proxy_ajp and cause     it to write 4 attacker controlled bytes after the end of a heap based buffer. This issue affects Apache     HTTP Server: through 2.4.66. Users are recommended to upgrade to version 2.4.67, which fixes the issue.
    (CVE-2026-28780)

  - Double Free and possible RCE vulnerability in Apache HTTP Server with the HTTP/2 protocol. This issue     affects Apache HTTP Server: 2.4.66. Users are recommended to upgrade to version 2.4.67, which fixes the     issue. (CVE-2026-23918)

  - An escalation of privilege bug in various modules in Apache HTTP 2.4.66 and earlier allows local .htaccess     authors to read files with the privileges of the httpd user. Users are recommended to upgrade to version     2.4.67, which fixes this issue. (CVE-2026-24072)

  - Allocation of Resources Without Limits or Throttling vulnerability in Apache HTTP Server's mod_md via OCSP     response data. This issue affects Apache HTTP Server: from 2.4.30 through 2.4.66. Users are recommended to     upgrade to version 2.4.67, which fixes the issue. (CVE-2026-29168)

  - A NULL pointer dereference in mod_dav_lock in Apache HTTP Server 2.4.66 and earlier may allow an attacker     to crash the server with a malicious request.mod_dav_lock is not used internally by mod_dav or mod_dav_fs.
    The only known use-case for mod_dav_lock was mod_dav_svn from Apache Subversion earlier than version     1.2.0. Users are recommended to upgrade to version 2.4.66, which fixes this issue, or remove mod_dav_lock.
    (CVE-2026-29169)

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

ID	Name	Product	Family	Severity
317663	SUSE SLED15 / SLES15 Security Update : apache2 (SUSE-SU-2026:2104-1)	Nessus	SuSE Local Security Checks	critical
317656	SUSE SLES15 Security Update : apache2 (SUSE-SU-2026:2103-1)	Nessus	SuSE Local Security Checks	critical
316988	Amazon Linux 2 : httpd, --advisory ALAS2-2026-3314 (ALAS-2026-3314)	Nessus	Amazon Linux Local Security Checks	critical
316833	Amazon Linux 2023 : httpd, httpd-core, httpd-devel (ALAS2023-2026-1720)	Nessus	Amazon Linux Local Security Checks	critical
316651	Fedora 43 : httpd (2026-0c87f546f8)	Nessus	Fedora Local Security Checks	critical
115232	Apache 2.4.x < 2.4.67 Multiple Vulnerabilities	Web App Scanning	Component Vulnerability	critical
313221	Debian dla-4571 : apache2 - security update	Nessus	Debian Local Security Checks	critical
313207	Ubuntu 22.04 LTS / 24.04 LTS / 25.10 / 26.04 LTS : Apache HTTP Server vulnerabilities (USN-8239-1)	Nessus	Ubuntu Local Security Checks	critical
312666	Debian dsa-6248 : apache2 - security update	Nessus	Debian Local Security Checks	critical
312249	FreeBSD : www/apache24 -- Multiple vulnerabilities (1ccc383b-486a-11f1-8b62-8447094a420f)	Nessus	FreeBSD Local Security Checks	critical
312236	Linux Distros Unpatched Vulnerability : CVE-2026-33006	Nessus	Misc.	medium
312108	Slackware Linux 15.0 / current httpd Multiple Vulnerabilities (SSA:2026-124-01)	Nessus	Slackware Local Security Checks	critical
311940	Apache 2.4.x < 2.4.67 Multiple Vulnerabilities	Nessus	Web Servers	critical

Detections

Analytics

CVE-2026-33006

medium

Tenable Plugins

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