When an FTP wildcard `LIST` operation fails, libcurl omits the restoration path meant for successful listings, leaving the write callback set to the internal listing parser and the write callback data pointing directly to the easy handle. Subsequent reuse of this handle triggers an immediate crash, and cloning it via `curl_easy_duphandle()` copies this corrupted state into the duplicate. If the original handle is subsequently freed, executing a transfer on the cloned handle causes a heap use-after-free read against the dangling handle reference; alternatively, reusing the original or cloned handle while changing only `CURLOPT_WRITEDATA` (and omitting `CURLOPT_WRITEFUNCTION`) results in type confusion, forcing the internal parser to interpret incoming server response bytes into memory at the application-supplied write data pointer.

The AlmaLinux 9.2 host has packages installed that are affected by multiple vulnerabilities as referenced in the TuxCare ALMALINUX9.2:CLSA-2026:1793725705 advisory.

  - When an FTP wildcard `LIST` operation fails, libcurl omits the restoration path meant for successful     listings, leaving the write callback set to the internal listing parser and the write callback data     pointing directly to the easy handle. Subsequent reuse of this handle triggers an immediate crash, and     cloning it via `curl_easy_duphandle()` copies this corrupted state into the duplicate. If the original     handle is subsequently freed, executing a transfer on the cloned handle causes a heap use-after-free read     against the dangling handle reference; alternatively, reusing the original or cloned handle while changing     only `CURLOPT_WRITEDATA` (and omitting `CURLOPT_WRITEFUNCTION`) results in type confusion, forcing the     internal parser to interpret incoming server response bytes into memory at the application-supplied write     data pointer. (CVE-2026-92388)

  - A deeply nested multipart MIME structure constructed via the public API causes a stack overflow in libcurl     during normal cleanup operations. An excessive recursion depth within `curl_mime_free` leads to unbounded     stack frame allocation during structure traversal, ultimately crashing the host process. (CVE-2026-92391)

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

The AlmaLinux 9.6 host has packages installed that are affected by multiple vulnerabilities as referenced in the TuxCare ALMALINUX9.6:CLSA-2026:1793725885 advisory.

  - When an FTP wildcard `LIST` operation fails, libcurl omits the restoration path meant for successful     listings, leaving the write callback set to the internal listing parser and the write callback data     pointing directly to the easy handle. Subsequent reuse of this handle triggers an immediate crash, and     cloning it via `curl_easy_duphandle()` copies this corrupted state into the duplicate. If the original     handle is subsequently freed, executing a transfer on the cloned handle causes a heap use-after-free read     against the dangling handle reference; alternatively, reusing the original or cloned handle while changing     only `CURLOPT_WRITEDATA` (and omitting `CURLOPT_WRITEFUNCTION`) results in type confusion, forcing the     internal parser to interpret incoming server response bytes into memory at the application-supplied write     data pointer. (CVE-2026-92388)

  - A deeply nested multipart MIME structure constructed via the public API causes a stack overflow in libcurl     during normal cleanup operations. An excessive recursion depth within `curl_mime_free` leads to unbounded     stack frame allocation during structure traversal, ultimately crashing the host process. (CVE-2026-92391)

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

The Rocky Linux 9.6 host has packages installed that are affected by multiple vulnerabilities as referenced in the TuxCare ALMALINUX9.6:CLSA-2026:1793725885 advisory.

  - When an FTP wildcard `LIST` operation fails, libcurl omits the restoration path meant for successful     listings, leaving the write callback set to the internal listing parser and the write callback data     pointing directly to the easy handle. Subsequent reuse of this handle triggers an immediate crash, and     cloning it via `curl_easy_duphandle()` copies this corrupted state into the duplicate. If the original     handle is subsequently freed, executing a transfer on the cloned handle causes a heap use-after-free read     against the dangling handle reference; alternatively, reusing the original or cloned handle while changing     only `CURLOPT_WRITEDATA` (and omitting `CURLOPT_WRITEFUNCTION`) results in type confusion, forcing the     internal parser to interpret incoming server response bytes into memory at the application-supplied write     data pointer. (CVE-2026-92388)

  - A deeply nested multipart MIME structure constructed via the public API causes a stack overflow in libcurl     during normal cleanup operations. An excessive recursion depth within `curl_mime_free` leads to unbounded     stack frame allocation during structure traversal, ultimately crashing the host process. (CVE-2026-92391)

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 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.

The CentOS Linux 7 host has packages installed that are affected by multiple vulnerabilities as referenced in the TuxCare CENTOS7:CLSA-2026:1793163761 advisory.

  - An HTTP proxy can trick libcurl into sending the origin's credentials (Basic password, or a     Negotiate/Kerberos ticket) to the proxy itself, by answering the `CONNECT` tunnel request with 401 `WWW-     Authenticate:` instead of the expected 407 `Proxy-Authenticate:`. (CVE-2026-86414)

  - When an FTP wildcard `LIST` operation fails, libcurl omits the restoration path meant for successful     listings, leaving the write callback set to the internal listing parser and the write callback data     pointing directly to the easy handle. Subsequent reuse of this handle triggers an immediate crash, and     cloning it via `curl_easy_duphandle()` copies this corrupted state into the duplicate. If the original     handle is subsequently freed, executing a transfer on the cloned handle causes a heap use-after-free read     against the dangling handle reference; alternatively, reusing the original or cloned handle while changing     only `CURLOPT_WRITEDATA` (and omitting `CURLOPT_WRITEFUNCTION`) results in type confusion, forcing the     internal parser to interpret incoming server response bytes into memory at the application-supplied write     data pointer. (CVE-2026-92388)

  - libcurl's TFTP state machine fails to validate state transitions against the requested transfer direction,     accepting opening server responses for both reads and writes interchangeably. A malicious TFTP server can     respond to a download request in a way that forces the client into transmit mode, prompting libcurl to     consume and transmit data from the handle's persistent `CURLOPT_READDATA` pointer - including data     remaining from unrelated prior operations, such as an HTTP POST request executed on a reused handle.
    (CVE-2026-92389)

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 7.21.0 prior to 8.23.0. It is, therefore, affected by a use-after-free vulnerability:

  - When an FTP wildcard LIST operation fails, libcurl omits the restoration path meant for     successful listings, leaving the write callback set to the internal listing parser and the     write callback data pointing directly to the easy handle. Subsequent reuse of this handle     triggers an immediate crash, and cloning it via curl_easy_duphandle() copies this corrupted     state into the duplicate. If the original handle is subsequently freed, executing a transfer     on the cloned handle causes a heap use-after-free read against the dangling handle reference;
    alternatively, reusing the original or cloned handle while changing only CURLOPT_WRITEDATA     (and omitting CURLOPT_WRITEFUNCTION) results in type confusion, forcing the internal parser     to interpret incoming server response bytes into memory at the application-supplied write data     pointer. (CVE-2026-92388)

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:

  - When an FTP wildcard `LIST` operation fails, libcurl omits the restoration path meant for successful
    listings, leaving the write callback set to the internal listing parser and the write callback data
    pointing directly to the easy handle. Subsequent reuse of this handle triggers an immediate crash, and
    cloning it via `curl_easy_duphandle()` copies this corrupted state into the duplicate. If the original
    handle is subsequently freed, executing a transfer on the cloned handle causes a heap use-after-free read
    against the dangling handle reference; alternatively, reusing the original or cloned handle while changing
    only `CURLOPT_WRITEDATA` (and omitting `CURLOPT_WRITEFUNCTION`) results in type confusion, forcing the
    internal parser to interpret incoming server response bytes into memory at the application-supplied write
    data pointer. (CVE-2026-92388)

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

  - When an FTP wildcard `LIST` operation fails, libcurl omits the restoration path meant for successful     listings, leaving the write callback set to the internal listing parser and the write callback data     pointing directly to the easy handle. Subsequent reuse of this handle triggers an immediate crash, and     cloning it via `curl_easy_duphandle()` copies this corrupted state into the duplicate. If the original     handle is subsequently freed, executing a transfer on the cloned handle causes a heap use-after-free read     against the dangling handle reference; alternatively, reusing the original or cloned handle while changing     only `CURLOPT_WRITEDATA` (and omitting `CURLOPT_WRITEFUNCTION`) results in type confusion, forcing the     internal parser to interpret incoming server response bytes into memory at the application-supplied write     data pointer. (CVE-2026-92388)

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

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 14dab969-c797-11f1-a6ea-8447094a420f advisory.

    The Curl project reports:

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.

ID	Name	Product	Family	Type	Severity
375530	AlmaLinux 9.2 [TuxCare] Security Update: curl / curl-minimal / libcurl / libcurl-devel / libcurl-minimal Multiple Vulnerabilities (ALMALINUX9.2:CLSA-2026:1793725705)	Nessus	Alma Linux Local Security Checks	Local	critical
375527	AlmaLinux 9.6 [TuxCare] Security Update: curl / curl-minimal / libcurl / libcurl-devel / libcurl-minimal Multiple Vulnerabilities (ALMALINUX9.6:CLSA-2026:1793725885)	Nessus	Alma Linux Local Security Checks	Local	critical
375523	Rocky Linux 9.6 [TuxCare] Security Update: curl / curl-minimal / libcurl / libcurl-devel / libcurl-minimal Multiple Vulnerabilities (ALMALINUX9.6:CLSA-2026:1793725885)	Nessus	Rocky Linux Local Security Checks	Local	critical
375384	SUSE SLED15 / SLES15 Security Update : curl (SUSE-SU-2026:4954-1)	Nessus	SuSE Local Security Checks	Local	critical
374851	CentOS Linux 7 [TuxCare] Security Update: curl / libcurl / libcurl-devel Multiple Vulnerabilities (CENTOS7:CLSA-2026:1793163761)	Nessus	CentOS 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
371154	Curl 7.21.0 < 8.23.0 FTP Wildcard Use-After-Free	Nessus	Misc.	Local	high
367202	Ubuntu 26.04 LTS : curl vulnerabilities (USN-8927-1)	Nessus	Ubuntu Local Security Checks	Local	critical
476130	Echo: curl: security update to 1:8.23.0-1+e1	Tenable Cloud Security	Echo Local Security Checks	Local	critical
476130	Echo: curl: security update to 1:8.23.0-1+e1	Tenable Self-Hosted Container Security	Echo Local Security Checks	Local	critical
365740	Linux Distros Unpatched Vulnerability : CVE-2026-92388	Nessus	Misc.	Local	critical
365567	FreeBSD : Curl -- Multiple vulnerabilities (14dab969-c797-11f1-a6ea-8447094a420f)	Nessus	FreeBSD Local Security Checks	Local	critical

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CVE-2026-92388

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