Detections
Analytics

Amazon Linux 2 : libpng12, --advisory ALAS2-2026-3243 (ALAS-2026-3243)

high Nessus Plugin ID 306301

Synopsis

The remote Amazon Linux 2 host is missing a security update.

Description

The version of libpng12 installed on the remote host is prior to 1.2.50-10. It is, therefore, affected by a vulnerability as referenced in the ALAS2-2026-3243 advisory.

 LIBPNG is a reference library for use in applications that read, create, and manipulate PNG (Portable Network Graphics) raster image files. In versions 1.2.1 through 1.6.55, `png_set_tRNS` and `png_set_PLTE` each alias a heap-allocated buffer between `png_struct` and `png_info`, sharing a single allocation across two structs with independent lifetimes. The `trans_alpha` aliasing has been present since at least libpng 1.0, and the `palette` aliasing since at least 1.2.1. Both affect all prior release lines `png_set_tRNS` sets `png_ptr->trans_alpha = info_ptr->trans_alpha` (256-byte buffer) and `png_set_PLTE` sets `info_ptr->palette = png_ptr->palette` (768-byte buffer). In both cases, calling `png_free_data` (with `PNG_FREE_TRNS` or `PNG_FREE_PLTE`) frees the buffer through `info_ptr` while the corresponding `png_ptr` pointer remains dangling. Subsequent row-transform functions dereference and, in some code paths, write to the freed memory. A second call to `png_set_tRNS` or `png_set_PLTE` has the same effect, because both functions call `png_free_data` internally before reallocating the `info_ptr` buffer. Version 1.6.56 fixes the issue.

 NOTE: https://github.com/pnggroup/libpng/security/advisories/GHSA-m4pc-p4q3-4c7jNOTE:
 https://github.com/pnggroup/libpng/pull/824NOTE: Fixed by:
 https://github.com/pnggroup/libpng/commit/23019269764e35ed8458e517f1897bd3c54820eb (v1.6.56)NOTE: Fixed by: https://github.com/pnggroup/libpng/commit/a3a21443ed12bfa1ef46fa0d4fb2b74a0fa34a25 (v1.6.56)NOTE:
 Fixed by: https://github.com/pnggroup/libpng/commit/7ea9eea884a2328cc7fdcb3c0c00246a50d90667 (v1.6.56)NOTE: Fixed by:
 https://github.com/pnggroup/libpng/commit/c1b0318b393c90679e6fa5bc1d329fd5d5012ec1 (v1.6.56) (CVE-2026-33416)

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

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

Solution

Run 'yum update libpng12' or or 'yum update --advisory ALAS2-2026-3243' to update your system.

See Also

https://alas.aws.amazon.com//AL2/ALAS2-2026-3243.html

https://alas.aws.amazon.com/faqs.html

https://explore.alas.aws.amazon.com/CVE-2026-33416.html

Plugin Details

Severity: High

ID: 306301

File Name: al2_ALAS-2026-3243.nasl

Version: 1.1

Type: Local

Agent: unix

Published: 4/14/2026

Updated: 4/14/2026

Supported Sensors: Continuous Assessment, Nessus Agent, Nessus

Risk Information

VPR

Risk Factor: High

Score: 7.4

CVSS v2

Risk Factor: High

Base Score: 7.6

Temporal Score: 6

Vector: CVSS2#AV:N/AC:H/Au:N/C:C/I:C/A:C

CVSS Score Source: CVE-2026-33416

CVSS v3

Risk Factor: High

Base Score: 7.5

Temporal Score: 6.7

Vector: CVSS:3.0/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H

Temporal Vector: CVSS:3.0/E:P/RL:O/RC:C

Vulnerability Information

CPE: p-cpe:/a:amazon:linux:libpng12, cpe:/o:amazon:linux:2, p-cpe:/a:amazon:linux:libpng12-devel, p-cpe:/a:amazon:linux:libpng12-debuginfo

Required KB Items: Host/local_checks_enabled, Host/AmazonLinux/release, Host/AmazonLinux/rpm-list

Exploit Available: true

Exploit Ease: Exploits are available

Patch Publication Date: 4/14/2026

Vulnerability Publication Date: 3/10/2026

Reference Information

CVE: CVE-2026-33416

IAVA: 2026-A-0272