==========================================================================
Ubuntu Security Notice USN-8251-1
May 07, 2026

libpng1.6 vulnerabilities
==========================================================================

A security issue affects these releases of Ubuntu and its derivatives:

- Ubuntu 25.10
- Ubuntu 24.04 LTS
- Ubuntu 22.04 LTS

Summary:

Several security issues were fixed in libpng.

Software Description:
- libpng1.6: PNG (Portable Network Graphics) file library

Details:

It was discovered that libpng incorrectly handled memory when processing
certain PNG files. If a user or automated system were tricked into opening
a specially crafted PNG file, an attacker could use this issue to cause
libpng to crash, resulting in a denial of service, or possibly execute
arbitrary code. (CVE-2026-33416)

It was discovered that libpng incorrectly handled expanding 8-bit paletted
rows to RGB or RGBA on ARM processors. If a user or automated system were
tricked into opening a specially crafted PNG file, an attacker could use
this issue to cause libpng to crash, resulting in a denial of service, or
possibly execute arbitrary code. (CVE-2026-33636)

It was discovered that libpng incorrectly handled certain setter APIs. An
attacker could possibly use this issue to obtain sensitive information.
(CVE-2026-34757)

Update instructions:

The problem can be corrected by updating your system to the following
package versions:

Ubuntu 25.10
  libpng16-16t64                  1.6.50-1ubuntu0.5

Ubuntu 24.04 LTS
  libpng16-16t64                  1.6.43-5ubuntu0.6

Ubuntu 22.04 LTS
  libpng16-16                     1.6.37-3ubuntu0.5

In general, a standard system update will make all the necessary changes.

References:
  https://ubuntu.com/security/notices/USN-8251-1
  CVE-2026-33416, CVE-2026-33636, CVE-2026-34757

Package Information:
  https://launchpad.net/ubuntu/+source/libpng1.6/1.6.50-1ubuntu0.5
  https://launchpad.net/ubuntu/+source/libpng1.6/1.6.43-5ubuntu0.6
  https://launchpad.net/ubuntu/+source/libpng1.6/1.6.37-3ubuntu0.5