There are packages installed that are affected by a vulnerability referenced in the following CVE:

  - Rack is a modular Ruby web server interface. Prior to versions 2.2.23, 3.1.21, and 3.2.6, Rack::Files#fail
    sets the Content-Length response header using String#size instead of String#bytesize. When the response
    body contains multibyte UTF-8 characters, the declared Content-Length is smaller than the number of bytes
    actually sent on the wire. Because Rack::Files reflects the requested path in 404 responses, an attacker
    can trigger this mismatch by requesting a non-existent path containing percent-encoded UTF-8 characters.
    This results in incorrect HTTP response framing and may cause response desynchronization in deployments
    that rely on the incorrect Content-Length value. This issue has been patched in versions 2.2.23, 3.1.21,
    and 3.2.6. (CVE-2026-34831)

The remote Ubuntu 14.04 LTS / 16.04 LTS / 18.04 LTS / 20.04 LTS / 22.04 LTS / 24.04 LTS / 25.10 host has packages installed that are affected by multiple vulnerabilities as referenced in the USN-8182-1 advisory.

    Andrew Lacambra discovered that Rack did not properly parse certain regular expressions. An attacker could     possibly use this issue to bypass network security filters. This issue only affected Ubuntu 20.04 LTS,     Ubuntu 22.04 LTS, Ubuntu 24.04 LTS, and Ubuntu 25.10. (CVE-2026-26961)

    William T. Nelson discovered that Rack did not handle multipart headers correctly. An attacker could     possibly use this issue to cause downstream parsing issues or a denial of service. This issue only     affected Ubuntu 25.10. (CVE-2026-26962)

    It was discovered that Rack did not handle the Forwarded header correctly. An attacker could possibly use     this issue to manipulate header values. This issue only affected Ubuntu 25.10. (CVE-2026-32762)

    It was discovered that Rack could consume excessive CPU when handling certain Accept-Encoding values. An     attacker could possibly use this issue to cause a denial of service. (CVE-2026-34230)

    Haruki Oyama discovered that certain configurations of Rack could erroneously fail to derive the displayed     directory path, and expose the full filesystem path. An attacker could possibly use this issue to disclose     deployment details such as layout and usernames. (CVE-2026-34763)

    It was discovered that Rack did not properly handle static file paths. An attacker could possibly use this     issue to exfiltrate unintentionally served data. (CVE-2026-34785)

    Haruki Oyama discovered that Rack did not apply header rules to certain requests for URL-encoded static     paths. An attacker could possibly use this issue to bypass security-relevant response headers. This issue     only affected Ubuntu 18.04 LTS, Ubuntu 20.04 LTS, Ubuntu 22.04 LTS, Ubuntu 24.04 LTS, and Ubuntu 25.10.
    (CVE-2026-34786)

    It was discovered that Rack did not limit the number of ranges requested in the Range header. An attacker     could possibly use this issue to cause a denial of service. This issue only affected Ubuntu 16.04 LTS,     Ubuntu 18.04 LTS, Ubuntu 20.04 LTS, Ubuntu 22.04 LTS, Ubuntu 24.04 LTS, and Ubuntu 25.10. (CVE-2026-34826)

    It was discovered that Rack could consume excessive CPU when parsing certain multipart parameters. An     attacker could possibly use this to cause a denial of service. This issue only affected Ubuntu 25.10.
    (CVE-2026-34827)

    It was discovered that Rack could consume unbounded disk space when handling requests without a Content-     Length header. An attacker could possibly use this issue to cause a denial of service. This issue only     affected Ubuntu 20.04 LTS, Ubuntu 22.04 LTS, Ubuntu 24.04 LTS, and Ubuntu 25.10. (CVE-2026-34829)

    Mehtab Zafar discovered that Rack directly interpreted the X-Accel-Mapping header as a regular expression     without escaping. An attacker could possibly use this issue to exfiltrate arbitrary files from internal     locations. This issue only affected Ubuntu 16.04 LTS, Ubuntu 18.04 LTS, Ubuntu 20.04 LTS, Ubuntu 22.04     LTS, Ubuntu 24.04 LTS, and Ubuntu 25.10. (CVE-2026-34830)

    It was discovered that Rack did not properly handle messages with Unicode. An attacker could possibly use     this issue to cause a denial of service. This issue only affected Ubuntu 22.04 LTS, Ubuntu 24.04 LTS, and     Ubuntu 25.10. (CVE-2026-34831)

    It was discovered that Rack did not properly parse the Host header. An attacker could possibly use this     issue to bypass security filters or poison generated links. This issue only affected Ubuntu 25.10.
    (CVE-2026-34835)

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 SUSE Linux SLES15 / SLES_SAP15 host has packages installed that are affected by multiple vulnerabilities as referenced in the SUSE-SU-2026:1745-1 advisory.

    Update to version 2.27.

    Security issues fixed:

    - CVE-2026-26961: rack: greedy multipart boundary parsing can lead to parser differentials and WAF bypass       (bsc#1261398).
    - CVE-2026-26962: rack: improper unfolding of folded multipart headers can lead to downstream header     injection and       response splitting(bsc#1261471).
    - CVE-2026-34763: rack: unescaped regex interpolation of configured root path can lead to root directory     disclosure       (bsc#1261406).
    - CVE-2026-34785: rack: prefix matching logic can lead to the exposure of unintended files under the     static root       (bsc#1261417).
    - CVE-2026-34786: rack: URL-encoded path mismatch can lead to `header_rules` bypass (bsc#1261426).
    - CVE-2026-34826: rack: missing individual byte range limit checks when parsing HTTP `Range` headers can     lead to       excessive resource consumption and a denial of service (bsc#1261436).
    - CVE-2026-34829: rack: multipart parsing without `Content-Length` header can lead to unbounded chunked     file uploads       and a denial of service (bsc#1261447).
    - CVE-2026-34230: rack: quadratic complexity when processing of wildcard `Accept-Encoding` headers can     lead to a denial       of service (bsc#1261388).
    - CVE-2026-34830: rack: improper sanitization of the `X-Accel-Mapping` request header can lead to the     exposure of       unintended files via `X-Accel-Redirect` (bsc#1261458).
    - CVE-2026-34831: rack: `Content-Length` header and body byte size mismatch when creating error responses     can lead to       incorrect HTTP response framing (bsc#1261466).

    Other updates and bugfixes:

    - Fix ReDoS in `Addressable`.
    - Fix out-of-bounds read in `rdiscount`.

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

  - Rack is a modular Ruby web server interface. Prior to versions 2.2.23, 3.1.21, and 3.2.6, Rack::Files#fail     sets the Content-Length response header using String#size instead of String#bytesize. When the response     body contains multibyte UTF-8 characters, the declared Content-Length is smaller than the number of bytes     actually sent on the wire. Because Rack::Files reflects the requested path in 404 responses, an attacker     can trigger this mismatch by requesting a non-existent path containing percent-encoded UTF-8 characters.
    This results in incorrect HTTP response framing and may cause response desynchronization in deployments     that rely on the incorrect Content-Length value. This issue has been patched in versions 2.2.23, 3.1.21,     and 3.2.6. (CVE-2026-34831)

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

The remote SUSE Linux SLES15 / SLES_SAP15 host has packages installed that are affected by multiple vulnerabilities as referenced in the SUSE-SU-2026:1964-1 advisory.

    This update for rmt-server fixes the following issues

    - CVE-2026-26961: rack: mismatch in header handling can allow to smuggle multipart content (bsc#1261398).
    - CVE-2026-26962: rack: improper unfolding of folded multipart headers can lead to header injection or     response       splitting (bsc#1261471).
    - CVE-2026-34230: rack: crafted Accept-Encoding header can cause a denial of service (bsc#1261388).
    - CVE-2026-34763: rack: failing of the prefix stripping can lead to information disclosure (bsc#1261406).
    - CVE-2026-34785: rack: prefix matching can expose unintended files under the static root (bsc#1261417).
    - CVE-2026-34786: rack: URL-encoded path mismatch can lead to `header_rules` bypass (bsc#1261426).
    - CVE-2026-34826: rack: multipart byte range processing can allow denial of service (bsc#1261436).
    - CVE-2026-34829: rack: multipart parsing without `Content-Length` header allows unbounded chunked file     uploads       (bsc#1261447).
    - CVE-2026-34830: rack: crafted `X-Accel-Mapping`headers can lead to regex injection (bsc#1261458).
    - CVE-2026-34831: rack: `Content-Length` mismatch can lead to incorrectly framed error responses     (bsc#1261466).

    Other fixes:

    - Update to version 2.27

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 Debian 11 / 12 host has a package installed that is affected by multiple vulnerabilities as referenced in the dla-4706 advisory.

    - -------------------------------------------------------------------------     Debian LTS Advisory DLA-4706-1                debian-lts@lists.debian.org     https://www.debian.org/lts/security/                          Abhijith PA     July 31, 2026                                 https://wiki.debian.org/LTS
    - -------------------------------------------------------------------------

    Package        : ruby-rack     Version        : 2.1.4-3+deb11u6 2.2.22-0+deb12u2     CVE ID         : CVE-2026-26961 CVE-2026-34230 CVE-2026-34763 CVE-2026-34785                      CVE-2026-34786 CVE-2026-34826 CVE-2026-34829 CVE-2026-34830                      CVE-2026-34831


    Multiple vulnerabilities were found in ruby-rack, a modular Ruby     webserver interface

    CVE-2026-26961

        Rack::Multipart::Parser extracts the boundary parameter from         multipart/form-data using a greedy regular expression. When a         Content-Type header contains multiple boundary parameters, Rack         selects the last one rather than the first. In deployments where         an upstream proxy, WAF, or intermediary interprets the first         boundary parameter, this mismatch can allow an attacker to smuggle         multipart content past upstream inspection and have Rack parse a         different body structure than the intermediary validated.

    CVE-2026-34230

        Rack::Utils.select_best_encoding processes Accept-Encoding values         with quadratic time complexity when the header contains many         wildcard (*) entries. Because this method is used by         Rack::Deflater to choose a response encoding, an unauthenticated         attacker can send a single request with a crafted Accept-Encoding         header and cause disproportionate CPU consumption on the         compression middleware path. This results in a denial of service         condition for applications using Rack::Deflater.

    CVE-2026-34763

        Rack::Directory interpolates the configured root path directly         into a regular expression when deriving the displayed directory         path. If root contains regex metacharacters such as +, *, or .,         the prefix stripping can fail and the generated directory listing         may expose the full filesystem path in the HTML output.

    CVE-2026-34785

        Rack::Static determines whether a request should be served as a         static file using a simple string prefix check. When configured         with URL prefixes such as /css, it matches any request path that         begins with that string, including unrelated paths such as         /css-config.env or /css-backup.sql. As a result, files under         the static root whose names merely share the configured prefix may         be served unintentionally, leading to information disclosure.

    CVE-2026-34786

        Rack::Static#applicable_rules evaluates several header_rules types         against the raw URL-encoded PATH_INFO, while the underlying         file-serving path is decoded before the file is served. As a         result, a request for a URL-encoded variant of a static path can         serve the same file without the headers that header_rules were         intended to apply. In deployments that rely on Rack::Static to         attach security-relevant response headers to static content, this         can allow an attacker to bypass those headers by requesting an         encoded form of the path.

    CVE-2026-34826

        Rack::Utils.get_byte_ranges parses the HTTP Range header without         limiting the number of individual byte ranges. Although the         existing fix for CVE-2024-26141 rejects ranges whose total byte         coverage exceeds the file size, it does not restrict the count of         ranges. An attacker can supply many small overlapping ranges such         as 0-0,0-0,0-0,... to trigger disproportionate CPU, memory, I/O,         and bandwidth consumption per request. This results in a denial of         service condition in Rack file-serving paths that process         multipart byte range responses.

    CVE-2026-34829

        Rack::Multipart::Parser only wraps the request body in a BoundedIO         when CONTENT_LENGTH is present. When a multipart/form-data request         is sent without a Content-Length header, such as with HTTP chunked         transfer encoding, multipart parsing continues until end-of-stream         with no total size limit. For file parts, the uploaded body is         written directly to a temporary file on disk rather than being         constrained by the buffered in-memory upload limit. An         unauthenticated attacker can therefore stream an arbitrarily large         multipart file upload and consume unbounded disk space. This         results in a denial of service condition for Rack applications         that accept multipart form data.

    CVE-2026-34830

        Rack::Sendfile#map_accel_path interpolates the value of the         X-Accel-Mapping request header directly into a regular expression         when rewriting file paths for X-Accel-Redirect. Because the header         value is not escaped, an attacker who can supply X-Accel-Mapping         to the backend can inject regex metacharacters and control the         generated X-Accel-Redirect response header. In deployments using         Rack::Sendfile with x-accel-redirect, this can allow an attacker         to cause nginx to serve unintended files from configured internal         locations.

    CVE-2026-34831

        Rack::Files#fail sets the Content-Length response header using         String#size instead of String#bytesize. When the response body         contains multibyte UTF-8 characters, the declared Content-Length         is smaller than the number of bytes actually sent on the         wire. Because Rack::Files reflects the requested path in 404         responses, an attacker can trigger this mismatch by requesting a         non-existent path containing percent-encoded UTF-8         characters. This results in incorrect HTTP response framing and         may cause response desynchronization in deployments that rely on         the incorrect Content-Length value.

    For Debian 11 bullseye, these problems have been fixed in version     2.1.4-3+deb11u6.

    For Debian 12 bookworm, these problems have been fixed in version     2.2.22-0+deb12u2.

    We recommend that you upgrade your ruby-rack packages.

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

    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 version of the Rack Ruby library installed on the remote host is prior to 2.2.23, prior to 3.1.21, or prior to 3.2.6.
It is, therefore, affected by multiple vulnerabilities:

  - Rack::Utils.get_byte_ranges parses HTTP Range header without limiting the number of individual byte ranges,     leading to denial of service (CVE-2026-34826)

  - Rack::Static uses simple string prefix check allowing unintended file disclosure (CVE-2026-34785)

  - Rack::Utils.select_best_encoding has quadratic time complexity with many wildcard Accept-Encoding     entries (CVE-2026-34230)

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-2026:2487-1 advisory.

    This update for rmt-server fixes the following issues

    - CVE-2026-26961: rack: mismatch in header handling can allow to smuggle multipart content (bsc#1261398).
    - CVE-2026-26962: rack: improper unfolding of folded multipart headers can lead to header injection or     response       splitting (bsc#1261471).
    - CVE-2026-34230: rack: crafted Accept-Encoding header can cause a denial of service (bsc#1261388).
    - CVE-2026-34763: rack: failing of the prefix stripping can lead to information disclosure (bsc#1261406).
    - CVE-2026-34785: rack: prefix matching can expose unintended files under the static root (bsc#1261417).
    - CVE-2026-34786: rack: URL-encoded path mismatch can lead to `header_rules` bypass (bsc#1261426).
    - CVE-2026-34826: rack: multipart byte range processing can allow denial of service (bsc#1261436).
    - CVE-2026-34829: rack: multipart parsing without `Content-Length` header allows unbounded chunked file     uploads       (bsc#1261447).
    - CVE-2026-34830: rack: crafted `X-Accel-Mapping`headers can lead to regex injection (bsc#1261458).
    - CVE-2026-34831: rack: `Content-Length` mismatch can lead to incorrectly framed error responses     (bsc#1261466).

    Changes for rmt-server:

    - Updated to version 2.27

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.

ID	Name	Product	Family	Published	Updated	Severity
439698	SCA: security update for rack (GHSA-q2ww-5357-x388)	Tenable Self-Hosted Container Security	SCA Checks	4/3/2026	7/2/2026	medium
439698	SCA: security update for rack (GHSA-q2ww-5357-x388)	Tenable Cloud Security	SCA Checks	4/3/2026	7/2/2026	medium
307009	Ubuntu 14.04 LTS / 16.04 LTS / 18.04 LTS / 20.04 LTS / 22.04 LTS / 24.04 LTS / 25.10 : Rack vulnerabilities (USN-8182-1)	Nessus	Ubuntu Local Security Checks	4/17/2026	4/17/2026	high
313640	SUSE SLES15 Security Update : rmt-server (SUSE-SU-2026:1745-1)	Nessus	SuSE Local Security Checks	5/10/2026	5/10/2026	high
304827	Linux Distros Unpatched Vulnerability : CVE-2026-34831	Nessus	Misc.	4/4/2026	7/30/2026	medium
315278	SUSE SLES15 Security Update : rmt-server (SUSE-SU-2026:1964-1)	Nessus	SuSE Local Security Checks	5/19/2026	5/19/2026	high
331301	Debian dla-4706 : ruby-rack - security update	Nessus	Debian Local Security Checks	7/30/2026	7/30/2026	high
305959	Ruby Rack < 2.2.23 / 3.0.x < 3.1.21 / 3.2 < 3.2.6 Multiple Vulnerabilities	Nessus	Misc.	4/10/2026	4/17/2026	high
322931	SUSE SLES15 Security Update : rmt-server (SUSE-SU-2026:2487-1)	Nessus	SuSE Local Security Checks	6/26/2026	6/26/2026	high

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