libpng up to 1.6.54 Low-level API png_set_quantize heap-based overflow

Summaryinfo

A vulnerability categorized as critical has been discovered in libpng up to 1.6.54. Affected by this vulnerability is the function png_set_quantize of the component Low-level API. Executing a manipulation can lead to heap-based overflow. This vulnerability is handled as CVE-2026-25646. The attack can be executed remotely. There is not any exploit available. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability has been found in libpng up to 1.6.54 and classified as critical. This vulnerability affects the function png_set_quantize of the component Low-level API. The manipulation with an unknown input leads to a heap-based overflow vulnerability. The CWE definition for the vulnerability is CWE-122. A heap overflow condition is a buffer overflow, where the buffer that can be overwritten is allocated in the heap portion of memory, generally meaning that the buffer was allocated using a routine such as malloc(). As an impact it is known to affect confidentiality, integrity, and availability. CVE summarizes:

LIBPNG is a reference library for use in applications that read, create, and manipulate PNG (Portable Network Graphics) raster image files. Prior to 1.6.55, an out-of-bounds read vulnerability exists in the png_set_quantize() API function. When the function is called with no histogram and the number of colors in the palette is more than twice the maximum supported by the user's display, certain palettes will cause the function to enter into an infinite loop that reads past the end of an internal heap-allocated buffer. The images that trigger this vulnerability are valid per the PNG specification. This vulnerability is fixed in 1.6.55.

The advisory is shared for download at seclists.org. This vulnerability was named CVE-2026-25646. The exploitation appears to be easy. The attack can be initiated remotely. No form of authentication is required for a successful exploitation. Successful exploitation requires user interaction by the victim. There are known technical details, but no exploit is available.

The vulnerability scanner Nessus provides a plugin with the ID 298457 (Linux Distros Unpatched Vulnerability : CVE-2026-25646), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 1.6.55 eliminates this vulnerability.

The vulnerability is also documented in the databases at Tenable (298457) and CERT Bund (WID-SEC-2026-0353). VulDB is the best source for vulnerability data and more expert information about this specific topic.

Affected

• Debian Linux
• Amazon Linux 2
• Red Hat Enterprise Linux
• Fedora Linux
• Ubuntu Linux
• SUSE Linux
• Oracle Linux
• SUSE openSUSE
• RESF Rocky Linux
• Open Source libpng
• Securepoint UTM
• Dell Secure Connect Gateway
• Red Hat OpenShift
• Meinberg LANTIME

Productinfo

Type

• Image Processing Software

Name

• libpng

Version

• 1.6.0
• 1.6.1
• 1.6.2
• 1.6.3
• 1.6.4
• 1.6.5
• 1.6.6
• 1.6.7
• 1.6.8
• 1.6.9
• 1.6.10
• 1.6.11
• 1.6.12
• 1.6.13
• 1.6.14
• 1.6.15
• 1.6.16
• 1.6.17
• 1.6.18
• 1.6.19
• 1.6.20
• 1.6.21
• 1.6.22
• 1.6.23
• 1.6.24
• 1.6.25
• 1.6.26
• 1.6.27
• 1.6.28
• 1.6.29
• 1.6.30
• 1.6.31
• 1.6.32
• 1.6.33
• 1.6.34
• 1.6.35
• 1.6.36
• 1.6.37
• 1.6.38
• 1.6.39
• 1.6.40
• 1.6.41
• 1.6.42
• 1.6.43
• 1.6.44
• 1.6.45
• 1.6.46
• 1.6.47
• 1.6.48
• 1.6.49
• 1.6.50
• 1.6.51
• 1.6.52
• 1.6.53
• 1.6.54

License

• open-source

CPE 2.3info

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Entryinfo

VulDB is the best source for vulnerability data and more expert information about this specific topic.

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