Enabling `CURLOPT_CRLF` causes curl to advertise the raw input byte count in the `IMAP APPEND {N}` literal while transmitting line-ending expanded data. The server reads only $N$ bytes for the payload, causing the remaining overflow bytes to be interpreted and executed as pipelined IMAP commands within the authenticated session.

suse_linux SUSE-SU-2026:5069-1: SUSE SLES15 : Security update for curl (Important) (SUSE-SU-2026:5069-1)

suse_linux SUSE-SU-2026:5068-1: SUSE SLED15 / SLES15 : Security update for curl (Important) (SUSE-SU-2026:5068-1)

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-2026:4954-1 advisory.

    - CVE-2026-8932: incomplete mTLS config matching in conn reuse (bsc#1268414).
    - CVE-2026-11856: cross-origin Digest auth state leak (bsc#1268426).
    - CVE-2026-18924: HTTP/2 server push UAF (bsc#1277477).
    - CVE-2026-19931: Negotiate ambient user conn reuse (bsc#1277478).
    - CVE-2026-80255: secure cookie attribute bypass with tab (bsc#1277482).
    - CVE-2026-82209: domain-scoped PSL domain cookie (bsc#1278173).
    - CVE-2026-86409: stale SigV4 headers sent unintended (bsc#1285031).
    - CVE-2026-86410: redirect to SFTP or SCP bypasses host verification (bsc#1285030).
    - CVE-2026-86414: leaking host credentials to HTTP proxy (bsc#1285026).
    - CVE-2026-87862: HSTS cache import drops longer-lived child (bsc#1285023).
    - CVE-2026-87863: HSTS response erases persisted entries (bsc#1285022).
    - CVE-2026-87864: IMAP APPEND plus CRLF conversion command injection (bsc#1285021).
    - CVE-2026-92386: server-set cookie aborts cookie jar load (bsc#1285018).
    - CVE-2026-92387: never-ending loop via server response omission (bsc#1285017).
    - CVE-2026-92388: FTP wildcard write callback mixup (bsc#1285016).
    - CVE-2026-92389: TFTP direction confusion (bsc#1285015).
    - CVE-2026-92390: -J no-clobber guarantee bypassed with 103 early hints (bsc#1285014).
    - CVE-2026-92391: curl_mime_free stack overflow by recursion (bsc#1285013).
    - CVE-2026-92392: HTTP/2 upload Use-After-Free (bsc#1285012).
    - CVE-2026-94266: password leak in CURLINFO_EFFECTIVE_URL (bsc#1285010).
    - CVE-2026-107929: local interface connection reuse mixup (bsc#1285008).

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.

There are packages installed that are affected by multiple vulnerabilities referenced in the following CVEs:

  - During an upload, curl mishandles HTTP/2 `RST_STREAM` received from the server (with reason
    `HTTP_1_1_REQUIRED` or `REFUSED_STREAM`) leading to a use after free of a `struct Curl_easy` object.
    (CVE-2026-92392)

  - Setting `CURLOPT_AWS_SIGV4` to NULL but does not disable SigV4 authentication, contrary to expectations
    and documentation. A subsequent transfer on the same handle still sends an `Authorization: AWS4-HMAC-
    SHA256` header to whatever URL isset next, leaking state information. (CVE-2026-86409)

  - A flaw in the curl command line tool's logic makes it only set SSH host verification options when
    interacting directly using SFTP or SCP, and not as a result of following a redirect. (CVE-2026-86410)

  - An `ftp://` transfer configured with `CURLUSESSL_NONE` can reuse a pooled FTP control connection that a
    previous easy handle upgraded with `STARTTLS` and authenticated using a client certificate. The second
    handle performs neither a new TLS handshake nor a new FTP login, so the server continues to authorize it
    under the first handle's certificate identity. (CVE-2026-86411)

  - A remote HTTP server can set a cookie that curl accepts and writes to a Netscape cookie jar but cannot
    reload. On the next invocation using the same path for `--cookie` and `--cookie-jar`, curl fails before
    connecting, then the cleanup procedure replaces the jar with an empty file, deleting cookies for unrelated
    domains. (CVE-2026-86412)

The version of curl installed on the remote host is 7.30.0 prior to 8.22.0. It is, therefore, affected by a command injection vulnerability:

  - Enabling CURLOPT_CRLF causes curl to advertise the raw input byte count in the IMAP APPEND     {N} literal while transmitting line-ending expanded data. The server reads only N bytes for     the payload, causing the remaining overflow bytes to be interpreted and executed as pipelined     IMAP commands within the authenticated session. (CVE-2026-87864)

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

The remote Ubuntu 26.04 LTS host has packages installed that are affected by multiple vulnerabilities as referenced in the USN-8927-1 advisory.

    It was discovered that curl, when built with GnuTLS support, had an out-of-bounds read in the WebSocket     send path. An attacker could possibly use this issue to obtain sensitive information. (CVE-2026-107928)

    Maksim discovered that curl did not correctly include the interface binding in connection reuse decisions     when CURLOPT_INTERFACE was used. An attacker could possibly use this issue to cause connections to go out     from an unintended source address. (CVE-2026-107929)

    Stanislav Fort discovered that curl did not properly clear AWS SigV4 authentication state when     CURLOPT_AWS_SIGV4 was set to NULL. An attacker could possibly use this issue to obtain sensitive     information. (CVE-2026-86409)

    Stanislav Fort discovered that the curl command line tool did not set SSH host verification options when     following redirects to SFTP or SCP URLs. An attacker could possibly use this issue to perform machine-in-     the-middle attacks. (CVE-2026-86410)

    Stanislav Fort discovered that curl did not properly handle cookie jar entries that could not be reloaded.
    An attacker could possibly use this issue to cause a denial of service. (CVE-2026-86412)

    Stanislav Fort discovered that an HTTP proxy could trick libcurl into sending credentials to the proxy     itself by responding to a CONNECT request with an unexpected authentication challenge. An attacker could     possibly use this issue to obtain sensitive information. (CVE-2026-86414)

    Stanislav Fort discovered that curl did not correctly handle HSTS entries when an includeSubDomains parent     entry was imported before a longer-lived child entry. An attacker could possibly use this issue to cause     curl to use unencrypted HTTP connections. (CVE-2026-87862)

    Stanislav Fort discovered that curl did not properly handle HSTS max-age values that exceeded calendar     time structure bounds. An attacker could possibly use this issue to cause a denial of service or data     loss. (CVE-2026-87863)

    Stanislav Fort discovered that curl did not properly handle IMAP APPEND commands when CURLOPT_CRLF was     enabled, allowing overflow bytes to be interpreted as pipelined commands. An authenticated attacker could     possibly use this issue to inject arbitrary IMAP commands. (CVE-2026-87864)

    Bobbeh Rhino discovered that libcurl, when used with libssh2 and a hashed known_hosts file, could     misreport a host key mismatch as a missing key. An attacker could possibly use this issue to perform     machine-in-the-middle attacks. (CVE-2026-87865)

    Joshua Rogers discovered that curl did not properly handle long cookie entries written to a Netscape     cookie jar. An attacker could possibly use this issue to cause a denial of service. (CVE-2026-92386)

    Joshua Rogers discovered that a malicious FTP, IMAP, POP3, or SMTP server could cause libcurl to block     indefinitely by omitting the final control-response line. An attacker could possibly use this issue to     cause a denial of service. (CVE-2026-92387)

    Joshua Rogers discovered that libcurl had a use-after-free vulnerability in the FTP wildcard matching     code. An attacker could possibly use this issue to cause curl to crash, resulting in a denial of service,     or execute arbitrary code. (CVE-2026-92388)

    Joshua Rogers discovered that libcurl's TFTP state machine did not properly validate transfer directions,     allowing a malicious server to force the client into transmit mode. An attacker could possibly use this     issue to obtain sensitive information. (CVE-2026-92389)

    Joshua Rogers discovered that curl did not properly enforce its file overwrite protection when using
    --remote-header-name in certain circumstances. An attacker could possibly use this issue to overwrite     local files. (CVE-2026-92390)

    Joshua Rogers discovered that curl had a stack overflow vulnerability when processing deeply nested MIME     structures. An attacker could possibly use this issue to cause curl to crash, resulting in a denial of     service. (CVE-2026-92391)

    Joshua Rogers discovered that libcurl could expose credentials in the URL returned by     CURLINFO_EFFECTIVE_URL when credentials were retrieved from a .netrc file. An attacker could possibly use     this issue to obtain sensitive information. (CVE-2026-94266)

    Joshua Rogers discovered that libcurl had a use-after-free vulnerability during HTTP/2 uploads when     handling RST_STREAM responses from the server. An attacker could possibly use this issue to cause curl to     crash, resulting in a denial of service, or execute arbitrary code. (CVE-2026-92392)

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.

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

  - Enabling `CURLOPT_CRLF` causes curl to advertise the raw input byte count in the `IMAP APPEND {N}` literal
    while transmitting line-ending expanded data. The server reads only $N$ bytes for the payload, causing the
    remaining overflow bytes to be interpreted and executed as pipelined IMAP commands within the
    authenticated session. (CVE-2026-87864)

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

  - Enabling `CURLOPT_CRLF` causes curl to advertise the raw input byte count in the `IMAP APPEND {N}` literal     while transmitting line-ending expanded data. The server reads only $N$ bytes for the payload, causing the     remaining overflow bytes to be interpreted and executed as pipelined IMAP commands within the     authenticated session. (CVE-2026-87864)

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

ID	Name	Product	Family	Type	Severity
375384	SUSE SLED15 / SLES15 Security Update : curl (SUSE-SU-2026:4954-1)	Nessus	SuSE Local Security Checks	Local	critical
477458	Alpine: libcurl, multiple curl packages: security update to 8.23.0-r0	Tenable Cloud Security	Alpine Linux Local Security Checks	Local	critical
477458	Alpine: libcurl, multiple curl packages: security update to 8.23.0-r0	Tenable Self-Hosted Container Security	Alpine Linux Local Security Checks	Local	critical
371155	Curl 7.30.0 < 8.22.0 IMAP Command Injection	Nessus	Misc.	Local	high
367202	Ubuntu 26.04 LTS : curl vulnerabilities (USN-8927-1)	Nessus	Ubuntu Local Security Checks	Local	critical
476127	Echo: curl: security update to 1:8.22.0-1+e1	Tenable Cloud Security	Echo Local Security Checks	Local	high
476127	Echo: curl: security update to 1:8.22.0-1+e1	Tenable Self-Hosted Container Security	Echo Local Security Checks	Local	high
365711	Linux Distros Unpatched Vulnerability : CVE-2026-87864	Nessus	Misc.	Local	high

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