CVE-2026-34757
LIBPNG has a yse-after-free in png_set_PLTE, png_set_tRNS and png_set_hIST leading to corrupted chunk data and potential heap information disclosure
Description
LIBPNG is a reference library for use in applications that read, create, and manipulate PNG (Portable Network Graphics) raster image files. From 1.0.9 to before 1.6.57, passing a pointer obtained from png_get_PLTE, png_get_tRNS, or png_get_hIST back into the corresponding setter on the same png_struct/png_info pair causes the setter to read from freed memory and copy its contents into the replacement buffer. The setter frees the internal buffer before copying from the caller-supplied pointer, which now dangles. The freed region may contain stale data (producing silently corrupted chunk metadata) or data from subsequent heap allocations (leaking unrelated heap contents into the chunk struct). This vulnerability is fixed in 1.6.57.
INFO
Published Date :
April 9, 2026, 3:16 p.m.
Last Modified :
May 13, 2026, 11:07 p.m.
Remotely Exploit :
No
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | MEDIUM | [email protected] | ||||
| CVSS 3.1 | MEDIUM | [email protected] |
Solution
- Update LIBPNG to version 1.6.57.
- Apply vendor patches for LIBPNG.
- Recompile applications linked against LIBPNG.
Public PoC/Exploit Available at Github
CVE-2026-34757 has a 1 public
PoC/Exploit available at Github.
Go to the Public Exploits tab to see the list.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-34757.
| URL | Resource |
|---|---|
| https://github.com/pnggroup/libpng/commit/398cbe3df03f4e11bb031e07f416dfdde3684e8a | Patch |
| https://github.com/pnggroup/libpng/commit/55d20aaa322c9274491cda82c5cd4f99b48c6bcc | Patch |
| https://github.com/pnggroup/libpng/issues/836 | Exploit Issue Tracking Mitigation |
| https://github.com/pnggroup/libpng/issues/837 | Exploit Issue Tracking Mitigation |
| https://github.com/pnggroup/libpng/security/advisories/GHSA-6fr7-g8h7-v645 | Mitigation Patch Vendor Advisory |
| https://lists.debian.org/debian-lts-announce/2026/05/msg00017.html | Mailing List Third Party Advisory |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-34757 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-34757
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
trivy-nginx-scan
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-34757 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-34757 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
Initial Analysis by [email protected]
May. 13, 2026
Action Type Old Value New Value Added CVSS V3.1 AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N Added CPE Configuration OR *cpe:2.3:a:libpng:libpng:*:*:*:*:*:*:*:* versions from (including) 1.0.9 up to (excluding) 1.6.57 Added CPE Configuration OR *cpe:2.3:o:debian:debian_linux:11.0:*:*:*:*:*:*:* Added Reference Type GitHub, Inc.: https://github.com/pnggroup/libpng/commit/398cbe3df03f4e11bb031e07f416dfdde3684e8a Types: Patch Added Reference Type GitHub, Inc.: https://github.com/pnggroup/libpng/commit/55d20aaa322c9274491cda82c5cd4f99b48c6bcc Types: Patch Added Reference Type GitHub, Inc.: https://github.com/pnggroup/libpng/issues/836 Types: Exploit, Issue Tracking, Mitigation Added Reference Type GitHub, Inc.: https://github.com/pnggroup/libpng/issues/837 Types: Exploit, Issue Tracking, Mitigation Added Reference Type GitHub, Inc.: https://github.com/pnggroup/libpng/security/advisories/GHSA-6fr7-g8h7-v645 Types: Mitigation, Patch, Vendor Advisory Added Reference Type CVE: https://lists.debian.org/debian-lts-announce/2026/05/msg00017.html Types: Mailing List, Third Party Advisory -
CVE Modified by af854a3a-2127-422b-91ae-364da2661108
May. 09, 2026
Action Type Old Value New Value Added Reference https://lists.debian.org/debian-lts-announce/2026/05/msg00017.html -
New CVE Received by [email protected]
Apr. 09, 2026
Action Type Old Value New Value Added Description LIBPNG is a reference library for use in applications that read, create, and manipulate PNG (Portable Network Graphics) raster image files. From 1.0.9 to before 1.6.57, passing a pointer obtained from png_get_PLTE, png_get_tRNS, or png_get_hIST back into the corresponding setter on the same png_struct/png_info pair causes the setter to read from freed memory and copy its contents into the replacement buffer. The setter frees the internal buffer before copying from the caller-supplied pointer, which now dangles. The freed region may contain stale data (producing silently corrupted chunk metadata) or data from subsequent heap allocations (leaking unrelated heap contents into the chunk struct). This vulnerability is fixed in 1.6.57. Added CVSS V3.1 AV:L/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N Added CWE CWE-416 Added Reference https://github.com/pnggroup/libpng/commit/398cbe3df03f4e11bb031e07f416dfdde3684e8a Added Reference https://github.com/pnggroup/libpng/commit/55d20aaa322c9274491cda82c5cd4f99b48c6bcc Added Reference https://github.com/pnggroup/libpng/issues/836 Added Reference https://github.com/pnggroup/libpng/issues/837 Added Reference https://github.com/pnggroup/libpng/security/advisories/GHSA-6fr7-g8h7-v645