In libexpat before 2.7.4, XML_ExternalEntityParserCreate does not copy unknown encoding handler user data.

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 027c6c07-065b-11f1-baae-589cfc023192 advisory.

    expat team reports:
    Update contains 2 security fixes:

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 remote Ubuntu 16.04 LTS / 18.04 LTS / 20.04 LTS / 22.04 LTS / 24.04 LTS host has packages installed that are affected by multiple vulnerabilities as referenced in the USN-8023-1 advisory.

    It was discovered that Expat, contained within the xmltok library, incorrectly handled the initialization     of parsers for external entities. An attacker could possibly use this issue to cause a denial of service.
    (CVE-2026-24515)

    It was discovered that Expat, contained within the xmltok library, incorrectly handled integer     calculations when allocating memory for XML tags. An attacker could possibly use this issue to cause a     denial of service or execute arbitrary code. (CVE-2026-25210)

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 Ubuntu 14.04 LTS / 16.04 LTS / 18.04 LTS / 20.04 LTS / 22.04 LTS / 25.10 host has packages installed that are affected by multiple vulnerabilities as referenced in the USN-8022-1 advisory.

    It was discovered that Expat incorrectly handled memory when parsing certain XML files. An attacker could     possibly use this issue to cause a denial of service. This issue was only addressed in Ubuntu 25.10.
    (CVE-2025-59375)

    It was discovered that Expat incorrectly handled the initialization of parsers for external entities. An     attacker could possibly use this issue to cause a denial of service. (CVE-2026-24515)

    It was discovered that Expat incorrectly handled integer calculations when allocating memory for XML tags.
    An attacker could possibly use this issue to cause a denial of service or execute arbitrary code.
    (CVE-2026-25210)

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.

An update of the expat package has been released.

According to its self-reported version, the Tenable Nessus application running on the remote host prior to 10.10.2, 10.11.0 prior to 10.11.2. It is, therefore, affected by multiple vulnerabilities as referenced in the TNS-2026-04 advisory.

  - In libexpat before 2.7.4, XML_ExternalEntityParserCreate does not copy unknown encoding handler user data.
    (CVE-2026-24515)

  - In libexpat before 2.7.4, the doContent function does not properly determine the buffer size bufSize     because there is no integer overflow check for tag buffer reallocation. (CVE-2026-25210)

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 expat installed on the remote host is prior to 2.7.4. It is, therefore, affected by multiple vulnerabilities as referenced in the SSA:2026-031-01 advisory.

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

Tenable has extracted the preceding description block directly from the expat 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.

  - In libexpat before 2.7.4, XML_ExternalEntityParserCreate does not copy unknown encoding handler user data.
    (CVE-2026-24515)

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

ID	Name	Product	Family	Severity
298957	FreeBSD : expat -- multiple vulnerabilities (027c6c07-065b-11f1-baae-589cfc023192)	Nessus	FreeBSD Local Security Checks	low
298808	Ubuntu 16.04 LTS / 18.04 LTS / 20.04 LTS / 22.04 LTS / 24.04 LTS : xmltok library vulnerabilities (USN-8023-1)	Nessus	Ubuntu Local Security Checks	low
298805	Ubuntu 14.04 LTS / 16.04 LTS / 18.04 LTS / 20.04 LTS / 22.04 LTS / 25.10 : Expat vulnerabilities (USN-8022-1)	Nessus	Ubuntu Local Security Checks	low
298353	Photon OS 5.0: Expat PHSA-2026-5.0-0756	Nessus	PhotonOS Local Security Checks	low
298226	Tenable Nessus < 10.10.2 / 10.11.0 < 10.11.2 Multiple Vulnerabilities (TNS-2026-04)	Nessus	Misc.	low
298019	Photon OS 4.0: Expat PHSA-2026-4.0-0956	Nessus	PhotonOS Local Security Checks	low
297491	Slackware Linux 15.0 / current expat Multiple Vulnerabilities (SSA:2026-031-01)	Nessus	Slackware Local Security Checks	low
296261	Linux Distros Unpatched Vulnerability : CVE-2026-24515	Nessus	Misc.	low

Detections

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CVE-2026-24515

low

Tenable Plugins

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