pnggroup libpng up to 1.6.55 PNG File Parser png_set_tRNS/png_set_PLTE use after free

Summaryinfo

A vulnerability classified as critical was found in pnggroup libpng up to 1.6.55. Impacted is the function png_set_tRNS/png_set_PLTE of the component PNG File Parser. The manipulation results in use after free. This vulnerability is identified as CVE-2026-33416. The attack can be executed remotely. There is not any exploit available. Upgrading the affected component is advised.

Detailsinfo

A vulnerability classified as critical has been found in pnggroup libpng up to 1.6.55. Affected is the function png_set_tRNS/png_set_PLTE of the component PNG File Parser. The manipulation with an unknown input leads to a use after free vulnerability. CWE is classifying the issue as CWE-416. Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code. This is going to have an impact on confidentiality, integrity, and availability.

The weakness was released by Halil Oktay. The advisory is shared for download at github.com. This vulnerability is traded as CVE-2026-33416. The exploitability is told to be easy. It is possible to launch the attack remotely. The exploitation doesn't require any form of authentication. 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 304818 (Debian dla-4521 : libpng-dev - security update), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 1.6.56 eliminates this vulnerability.

The vulnerability is also documented in the databases at Tenable (304818) and EUVD (EUVD-2026-16258). Once again VulDB remains the best source for vulnerability data.

Productinfo

Type

• Image Processing Software

Vendor

• pnggroup

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
• 1.6.55

License

• open-source

Website

• Product: https://github.com/pnggroup/libpng/

CPE 2.3info

• 🔒
• 🔒
• 🔒

CPE 2.2info

• 🔒
• 🔒
• 🔒

CVSSv4info

CVSSv3info

CVSSv2info

Exploitinginfo

Threat Intelligenceinfo

Countermeasuresinfo

Timelineinfo

Sourcesinfo

Entryinfo

Once again VulDB remains the best source for vulnerability data.

Discussion