An out-of-bounds read vulnerability in libX11's XIM trigger-key registration parser in libX11 before 1.8.14 could be used by malicious X servers to crash attached X clients.

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

  - A malicious X server could exploit a buffer overflow in libX11 before 1.8.14 during handling of XkbGetMap
    overflowing the key_sym_map. (CVE-2026-88806)

  - An out-of-bounds read vulnerability in libX11's XIM (X Input Method) attribute parser in libX11 before
    1.8.14 could be used by malicious X servers to crash attached X clients. (CVE-2026-94283)

  - An out-of-bounds read vulnerability in libX11's XIM trigger-key registration parser in libX11 before
    1.8.14 could be used by malicious X servers to crash attached X clients. (CVE-2026-94284)

  - An out-of-bounds read in libX11's byte-oriented codeset parser in libX11 before 1.8.14 could be used by
    malicious X servers to crash attached X clients. (CVE-2026-94285)

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 fbf59c13-ca23-11f1-ada1-ac5afc632ba3 advisory.

    X.Org reports:
    Multiple issues have been found in the X client library               implementations published by X.Org for which we are               releasing security fixes for.

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 version of libX11 installed on the remote host is prior to 1.8.14. It is, therefore, affected by multiple vulnerabilities as referenced in the SSA:2026-289-01 advisory.

    New libX11 packages are available for Slackware 15.0 and -current to fix security issues.

Tenable has extracted the preceding description block directly from the libX11 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 14.04 LTS / 16.04 LTS / 18.04 LTS / 20.04 LTS / 22.04 LTS / 24.04 LTS / 26.04 LTS host has packages installed that are affected by multiple vulnerabilities as referenced in the USN-8913-1 advisory.

    Adam Bedard discovered that libx11 incorrectly handled certain XKB keyboard map replies. If a user were     tricked into connecting to a malicious X server, a remote attacker could possibly use this issue to cause     libx11 to crash, resulting in a denial of service, or possibly execute arbitrary code. (CVE-2026-88806)

    It was discovered that libx11 incorrectly handled certain X Input Method (XIM) messages. If a user were     tricked into connecting to a malicious X server, a remote attacker could possibly use these issues to     cause libx11 to crash, resulting in a denial of service. (CVE-2026-94283, CVE-2026-94284)

    It was discovered that libx11 incorrectly handled converting certain multibyte text. An attacker could     possibly use this issue to cause libx11 to crash, resulting in a denial of service. (CVE-2026-94285)

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-2026:4501-1 advisory.

    - CVE-2026-88806: XkbGetMap Reply Heap-based Buffer Overflow (bsc#1280910).
    - CVE-2026-94283: out-of-bounds read vulnerability in libX11's XIM (X Input Method) attribute parser     (bsc#1281653).
    - CVE-2026-94284: out-of-bounds read vulnerability in libX11's XIM trigger-keyregistration     parser.registration parser       (bsc#1281657).
    - CVE-2026-94285: out-of-bounds read in libX11's byte-oriented codeset parser (bsc#1281661).

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 SLED15 / SLED_SAP15 / SLES15 / SLES_SAP15 host has packages installed that are affected by multiple vulnerabilities as referenced in the SUSE-SU-2026:4502-1 advisory.

    - CVE-2026-88806: XkbGetMap Reply Heap-based Buffer Overflow (bsc#1280910).
    - CVE-2026-94283: out-of-bounds read vulnerability in libX11's XIM (X Input Method) attribute parser     (bsc#1281653).
    - CVE-2026-94284: out-of-bounds read vulnerability in libX11's XIM trigger-keyregistration     parser.registration parser       (bsc#1281657).
    - CVE-2026-94285: out-of-bounds read in libX11's byte-oriented codeset parser (bsc#1281661).

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-2026:4500-1 advisory.

    - CVE-2026-88806: XkbGetMap Reply Heap-based Buffer Overflow (bsc#1280910).
    - CVE-2026-94283: out-of-bounds read vulnerability in libX11's XIM (X Input Method) attribute parser     (bsc#1281653).
    - CVE-2026-94284: out-of-bounds read vulnerability in libX11's XIM trigger-keyregistration     parser.registration parser       (bsc#1281657).
    - CVE-2026-94285: out-of-bounds read in libX11's byte-oriented codeset parser (bsc#1281661).

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 a vulnerability referenced in the following CVE:

  - An out-of-bounds read vulnerability in libX11's XIM trigger-key registration parser in libX11 before
    1.8.14 could be used by malicious X servers to crash attached X clients. (CVE-2026-94284)

The remote SUSE Linux SLES12 / SLES_SAP12 host has packages installed that are affected by multiple vulnerabilities as referenced in the SUSE-SU-2026:4410-1 advisory.

    - CVE-2026-88806: XkbGetMap Reply Heap-based Buffer Overflow (bsc#1280910).
    - CVE-2026-94283: out-of-bounds read vulnerability in libX11's XIM (X Input Method) attribute parser     (bsc#1281653).
    - CVE-2026-94284: out-of-bounds read vulnerability in libX11's XIM trigger-keyregistration     parser.registration parser       (bsc#1281657).
    - CVE-2026-94285: out-of-bounds read in libX11's byte-oriented codeset parser (bsc#1281661).

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.

  - An out-of-bounds read vulnerability in libX11's XIM trigger-key registration parser in libX11 before     1.8.14 could be used by malicious X servers to crash attached X clients. (CVE-2026-94284)

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

ID	Name	Product	Family	Type	Severity
476149	Alpine: libx11: security update to 1.8.14-r0	Tenable Cloud Security	Alpine Linux Local Security Checks	Local	high
476149	Alpine: libx11: security update to 1.8.14-r0	Tenable Self-Hosted Container Security	Alpine Linux Local Security Checks	Local	high
366972	FreeBSD : libX11 -- multiple vulnerabilities (fbf59c13-ca23-11f1-ada1-ac5afc632ba3)	Nessus	FreeBSD Local Security Checks	Local	high
366686	Slackware Linux 15.0 / current libX11 Multiple Vulnerabilities (SSA:2026-289-01)	Nessus	Slackware Local Security Checks	Local	high
365763	Ubuntu 14.04 LTS / 16.04 LTS / 18.04 LTS / 20.04 LTS / 22.04 LTS / 24.04 LTS / 26.04 LTS : libx11 vulnerabilities (USN-8913-1)	Nessus	Ubuntu Local Security Checks	Local	high
363081	SUSE SLES15: libX11-6 / libX11-6-32bit / libX11-data / libX11-devel / etc (SUSE-SU-2026:4501-1)	Nessus	SuSE Local Security Checks	Local	high
363066	SUSE SLED15: libX11-6 / libX11-6-32bit / libX11-data / libX11-devel / etc (SUSE-SU-2026:4502-1)	Nessus	SuSE Local Security Checks	Local	high
363064	SUSE SLES15: libX11-6 / libX11-6-32bit / libX11-data / libX11-devel / etc (SUSE-SU-2026:4500-1)	Nessus	SuSE Local Security Checks	Local	high
465302	Echo: libx11: security update to 2:1.8.12-1+e2	Tenable Cloud Security	Echo Local Security Checks	Local	medium
465302	Echo: libx11: security update to 2:1.8.12-1+e2	Tenable Self-Hosted Container Security	Echo Local Security Checks	Local	medium
362573	SUSE SLES12: libX11-6 / libX11-6-32bit / libX11-data / libX11-devel / etc (SUSE-SU-2026:4410-1)	Nessus	SuSE Local Security Checks	Local	high
350906	Linux Distros Unpatched Vulnerability : CVE-2026-94284	Nessus	Misc.	Local	medium

Detections

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CVE-2026-94284

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Tenable Plugins

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