LIBPNG is a reference library for use in applications that process PNG (Portable Network Graphics) raster image files. In version 1.8.0, three inter-frame chunk discard paths in the push-mode APNG parser clear the chunk-header flag without consuming the chunk body and CRC, allowing attacker-controlled bytes inside an ignored ancillary chunk to be reinterpreted as a fresh chunk header on the next call to `png_process_data`. Commit faf06924688b62d7c1654b5ceddedbde66ffadb4 fixes the issue.

The version of thunderbird installed on the remote host is prior to 140.11.1-1. It is, therefore, affected by multiple vulnerabilities as referenced in the ALAS2-2026-3340 advisory.

    Three inter-frame chunk discard paths in the push-mode APNG parser clear the chunk-header flag without     consuming the chunk body and CRC, allowing attacker-controlled bytes inside an ignored ancillary chunk to     be reinterpreted as a fresh chunk header on the next call to png_process_data (CVE-2026-40930)

    Incorrect boundary conditions in the Audio/Video: Web Codecs component. This vulnerability was fixed in     Firefox 151, Firefox ESR 115.36, Firefox ESR 140.11, Thunderbird 151, and Thunderbird 140.11.
    (CVE-2026-8946)

    Use-after-free in the DOM: Bindings (WebIDL) component. This vulnerability was fixed in Firefox 151,     Firefox ESR 115.36, Firefox ESR 140.11, Thunderbird 151, and Thunderbird 140.11. (CVE-2026-8947)

    Same-origin policy bypass in the Networking: HTTP component. This vulnerability was fixed in Firefox 151,     Firefox ESR 140.11, Thunderbird 151, and Thunderbird 140.11. (CVE-2026-8950)

    Sandbox escape due to use-after-free in the Disability Access APIs component. This vulnerability was fixed     in Firefox 151, Firefox ESR 115.36, Firefox ESR 140.11, Thunderbird 151, and Thunderbird 140.11.
    (CVE-2026-8953)

    Incorrect boundary conditions, integer overflow in the Audio/Video component. This vulnerability was fixed     in Firefox 151, Firefox ESR 140.11, Thunderbird 151, and Thunderbird 140.11. (CVE-2026-8954)

    Privilege escalation in the DOM: Workers component. This vulnerability was fixed in Firefox 151, Firefox     ESR 140.11, Thunderbird 151, and Thunderbird 140.11. (CVE-2026-8955)

    Integer overflow in the Networking: JAR component. This vulnerability was fixed in Firefox 151, Firefox     ESR 140.11, Thunderbird 151, and Thunderbird 140.11. (CVE-2026-8956)

    Privilege escalation in the Enterprise Policies component. This vulnerability was fixed in Firefox 151,     Firefox ESR 140.11, Thunderbird 151, and Thunderbird 140.11. (CVE-2026-8957)

    Information disclosure, sandbox escape in the Security: Process Sandboxing component. This vulnerability     was fixed in Firefox 151, Firefox ESR 140.11, Thunderbird 151, and Thunderbird 140.11. (CVE-2026-8958)

    Spoofing issue in the Form Autofill component. This vulnerability was fixed in Firefox 151, Firefox ESR     140.11, Thunderbird 151, and Thunderbird 140.11. (CVE-2026-8961)

    Mitigation bypass in the DOM: Security component. This vulnerability was fixed in Firefox 151, Firefox ESR     140.11, Thunderbird 151, and Thunderbird 140.11. (CVE-2026-8962)

    Denial-of-service due to invalid pointer in the Audio/Video: Web Codecs component. This vulnerability was     fixed in Firefox 151, Firefox ESR 140.11, Thunderbird 151, and Thunderbird 140.11. (CVE-2026-8968)

    Privilege escalation in the Security component. This vulnerability was fixed in Firefox 151, Firefox ESR     140.11, Thunderbird 151, and Thunderbird 140.11. (CVE-2026-8970)

    Memory safety bugs present in Thunderbird 140.10 and Thunderbird 150. Some of these bugs showed evidence     of memory corruption and we presume that with enough effort some of these could have been exploited to run     arbitrary code. This vulnerability was fixed in Firefox 151, Firefox ESR 140.11, Thunderbird 151, and     Thunderbird 140.11. (CVE-2026-8974)

    Memory safety bugs present in Thunderbird 140.10 and Thunderbird 150. Some of these bugs showed evidence     of memory corruption and we presume that with enough effort some of these could have been exploited to run     arbitrary code. This vulnerability was fixed in Firefox 151, Firefox ESR 115.36, Firefox ESR 140.11,     Thunderbird 151, and Thunderbird 140.11. (CVE-2026-8975)

Tenable has extracted the preceding description block directly from the tested product security advisory.

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

It is, therefore, affected by multiple vulnerabilities as referenced in the ALAS2023-2026-1793 advisory.

    Three inter-frame chunk discard paths in the push-mode APNG parser clear the chunk-header flag without     consuming the chunk body and CRC, allowing attacker-controlled bytes inside an ignored ancillary chunk to     be reinterpreted as a fresh chunk header on the next call to png_process_data (CVE-2026-40930)

    Incorrect boundary conditions in the Audio/Video: Web Codecs component. This vulnerability was fixed in     Firefox 151, Firefox ESR 115.36, Firefox ESR 140.11, Thunderbird 151, and Thunderbird 140.11.
    (CVE-2026-8946)

    Use-after-free in the DOM: Bindings (WebIDL) component. This vulnerability was fixed in Firefox 151,     Firefox ESR 115.36, Firefox ESR 140.11, Thunderbird 151, and Thunderbird 140.11. (CVE-2026-8947)

    Same-origin policy bypass in the Networking: HTTP component. This vulnerability was fixed in Firefox 151,     Firefox ESR 140.11, Thunderbird 151, and Thunderbird 140.11. (CVE-2026-8950)

    Sandbox escape due to use-after-free in the Disability Access APIs component. This vulnerability was fixed     in Firefox 151, Firefox ESR 115.36, Firefox ESR 140.11, Thunderbird 151, and Thunderbird 140.11.
    (CVE-2026-8953)

    Incorrect boundary conditions, integer overflow in the Audio/Video component. This vulnerability was fixed     in Firefox 151, Firefox ESR 140.11, Thunderbird 151, and Thunderbird 140.11. (CVE-2026-8954)

    Privilege escalation in the DOM: Workers component. This vulnerability was fixed in Firefox 151, Firefox     ESR 140.11, Thunderbird 151, and Thunderbird 140.11. (CVE-2026-8955)

    Integer overflow in the Networking: JAR component. This vulnerability was fixed in Firefox 151, Firefox     ESR 140.11, Thunderbird 151, and Thunderbird 140.11. (CVE-2026-8956)

    Privilege escalation in the Enterprise Policies component. This vulnerability was fixed in Firefox 151,     Firefox ESR 140.11, Thunderbird 151, and Thunderbird 140.11. (CVE-2026-8957)

    Information disclosure, sandbox escape in the Security: Process Sandboxing component. This vulnerability     was fixed in Firefox 151, Firefox ESR 140.11, Thunderbird 151, and Thunderbird 140.11. (CVE-2026-8958)

    Spoofing issue in the Form Autofill component. This vulnerability was fixed in Firefox 151, Firefox ESR     140.11, Thunderbird 151, and Thunderbird 140.11. (CVE-2026-8961)

    Mitigation bypass in the DOM: Security component. This vulnerability was fixed in Firefox 151, Firefox ESR     140.11, Thunderbird 151, and Thunderbird 140.11. (CVE-2026-8962)

    Denial-of-service due to invalid pointer in the Audio/Video: Web Codecs component. This vulnerability was     fixed in Firefox 151, Firefox ESR 140.11, Thunderbird 151, and Thunderbird 140.11. (CVE-2026-8968)

    Privilege escalation in the Security component. This vulnerability was fixed in Firefox 151, Firefox ESR     140.11, Thunderbird 151, and Thunderbird 140.11. (CVE-2026-8970)

    Memory safety bugs present in Thunderbird 140.10 and Thunderbird 150. Some of these bugs showed evidence     of memory corruption and we presume that with enough effort some of these could have been exploited to run     arbitrary code. This vulnerability was fixed in Firefox 151, Firefox ESR 140.11, Thunderbird 151, and     Thunderbird 140.11. (CVE-2026-8974)

    Memory safety bugs present in Thunderbird 140.10 and Thunderbird 150. Some of these bugs showed evidence     of memory corruption and we presume that with enough effort some of these could have been exploited to run     arbitrary code. This vulnerability was fixed in Firefox 151, Firefox ESR 115.36, Firefox ESR 140.11,     Thunderbird 151, and Thunderbird 140.11. (CVE-2026-8975)

Tenable has extracted the preceding description block directly from the tested product 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 firefox installed on the remote host is prior to 140.11.0-1. It is, therefore, affected by multiple vulnerabilities as referenced in the ALAS2FIREFOX-2026-061 advisory.

    Three inter-frame chunk discard paths in the push-mode APNG parser clear the chunk-header flag without     consuming the chunk body and CRC, allowing attacker-controlled bytes inside an ignored ancillary chunk to     be reinterpreted as a fresh chunk header on the next call to png_process_data (CVE-2026-40930)

    Incorrect boundary conditions in the Audio/Video: Web Codecs component. This vulnerability was fixed in     Firefox 151, Firefox ESR 115.36, Firefox ESR 140.11, Thunderbird 151, and Thunderbird 140.11.
    (CVE-2026-8946)

    Use-after-free in the DOM: Bindings (WebIDL) component. This vulnerability was fixed in Firefox 151,     Firefox ESR 115.36, Firefox ESR 140.11, Thunderbird 151, and Thunderbird 140.11. (CVE-2026-8947)

    Same-origin policy bypass in the Networking: HTTP component. This vulnerability was fixed in Firefox 151,     Firefox ESR 140.11, Thunderbird 151, and Thunderbird 140.11. (CVE-2026-8950)

    Sandbox escape due to use-after-free in the Disability Access APIs component. This vulnerability was fixed     in Firefox 151, Firefox ESR 115.36, Firefox ESR 140.11, Thunderbird 151, and Thunderbird 140.11.
    (CVE-2026-8953)

    Incorrect boundary conditions, integer overflow in the Audio/Video component. This vulnerability was fixed     in Firefox 151, Firefox ESR 140.11, Thunderbird 151, and Thunderbird 140.11. (CVE-2026-8954)

    Privilege escalation in the DOM: Workers component. This vulnerability was fixed in Firefox 151, Firefox     ESR 140.11, Thunderbird 151, and Thunderbird 140.11. (CVE-2026-8955)

    Integer overflow in the Networking: JAR component. This vulnerability was fixed in Firefox 151, Firefox     ESR 140.11, Thunderbird 151, and Thunderbird 140.11. (CVE-2026-8956)

    Privilege escalation in the Enterprise Policies component. This vulnerability was fixed in Firefox 151,     Firefox ESR 140.11, Thunderbird 151, and Thunderbird 140.11. (CVE-2026-8957)

    Information disclosure, sandbox escape in the Security: Process Sandboxing component. This vulnerability     was fixed in Firefox 151, Firefox ESR 140.11, Thunderbird 151, and Thunderbird 140.11. (CVE-2026-8958)

    Spoofing issue in the Form Autofill component. This vulnerability was fixed in Firefox 151, Firefox ESR     140.11, Thunderbird 151, and Thunderbird 140.11. (CVE-2026-8961)

    Mitigation bypass in the DOM: Security component. This vulnerability was fixed in Firefox 151, Firefox ESR     140.11, Thunderbird 151, and Thunderbird 140.11. (CVE-2026-8962)

    Denial-of-service due to invalid pointer in the Audio/Video: Web Codecs component. This vulnerability was     fixed in Firefox 151, Firefox ESR 140.11, Thunderbird 151, and Thunderbird 140.11. (CVE-2026-8968)

    Privilege escalation in the Security component. This vulnerability was fixed in Firefox 151, Firefox ESR     140.11, Thunderbird 151, and Thunderbird 140.11. (CVE-2026-8970)

    Memory safety bugs present in Thunderbird 140.10 and Thunderbird 150. Some of these bugs showed evidence     of memory corruption and we presume that with enough effort some of these could have been exploited to run     arbitrary code. This vulnerability was fixed in Firefox 151, Firefox ESR 140.11, Thunderbird 151, and     Thunderbird 140.11. (CVE-2026-8974)

    Memory safety bugs present in Thunderbird 140.10 and Thunderbird 150. Some of these bugs showed evidence     of memory corruption and we presume that with enough effort some of these could have been exploited to run     arbitrary code. This vulnerability was fixed in Firefox 151, Firefox ESR 115.36, Firefox ESR 140.11,     Thunderbird 151, and Thunderbird 140.11. (CVE-2026-8975)

Tenable has extracted the preceding description block directly from the tested product 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:

  - LIBPNG is a reference library for use in applications that process PNG (Portable Network Graphics) raster
    image files. In version 1.8.0, three inter-frame chunk discard paths in the push-mode APNG parser clear
    the chunk-header flag without consuming the chunk body and CRC, allowing attacker-controlled bytes inside
    an ignored ancillary chunk to be reinterpreted as a fresh chunk header on the next call to
    `png_process_data`. Commit faf06924688b62d7c1654b5ceddedbde66ffadb4 fixes the issue. (CVE-2026-40930)

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

  - LIBPNG is a reference library for use in applications that process PNG (Portable Network Graphics) raster     image files. In version 1.8.0, three inter-frame chunk discard paths in the push-mode APNG parser clear     the chunk-header flag without consuming the chunk body and CRC, allowing attacker-controlled bytes inside     an ignored ancillary chunk to be reinterpreted as a fresh chunk header on the next call to     `png_process_data`. Commit faf06924688b62d7c1654b5ceddedbde66ffadb4 fixes the issue. (CVE-2026-40930)

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

ID	Name	Product	Family	Severity
319829	Amazon Linux 2 : thunderbird, --advisory ALAS2-2026-3340 (ALAS-2026-3340)	Nessus	Amazon Linux Local Security Checks	critical
319826	Amazon Linux 2023 : firefox (ALAS2023-2026-1793)	Nessus	Amazon Linux Local Security Checks	critical
319773	Amazon Linux 2 : firefox, --advisory ALAS2FIREFOX-2026-061 (ALASFIREFOX-2026-061)	Nessus	Amazon Linux Local Security Checks	critical
442022	Alpine: multiple libpng packages: security update to 1.6.58-r1	Tenable Cloud Security	Alpine Linux Local Security Checks	medium
442022	Alpine: multiple libpng packages: security update to 1.6.58-r1	Tenable Self-Hosted Container Security	Alpine Linux Local Security Checks	medium
315007	Linux Distros Unpatched Vulnerability : CVE-2026-40930	Nessus	Misc.	medium

Detections

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CVE-2026-40930

medium

Tenable Plugins

critical

critical

critical

medium

medium

medium