CVE-2026-34757: pnggroup libpng · Use After Free
Affects pnggroup libpngSource CVE Database V5
Not known to be exploited · CVSS 5.1 Medium : upgrade to 1.6.57 when convenient.
Data as of 30 Oct 2026, 06:59 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 9% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 1.6.57
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:NExploitation evidence
Disclosed: evidence found.
CVE published 9 Apr 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 29 Oct 2026.
What to do
Upgrade libpng and pnggroup/libpng to 1.6.57.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| pnggrouplibpng | Affected
| Fixed in
|
GitHubpnggroup/libpngpkg:github/pnggroup/libpngOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
This vulnerability is fixed in libpng version 1.6.57. Users and developers should upgrade to version 1.6.57 or later to remediate this issue. Patch status is not explicitly confirmed in the vendor advisory beyond the stated fix version, so users should verify with the official libpng release notes or vendor advisory for confirmation.
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.
References
- github.com/pnggroup/libpng/security/advisories/GHSA-6fr7-g8h7-v645 (opens in a new tab)
- github.com/pnggroup/libpng/issues/836 (opens in a new tab)
- github.com/pnggroup/libpng/issues/837 (opens in a new tab)
- github.com/pnggroup/libpng/commit/398cbe3df03f4e11bb031e07f416dfdde3684e8a (opens in a new tab)
- github.com/pnggroup/libpng/commit/55d20aaa322c9274491cda82c5cd4f99b48c6bcc (opens in a new tab)
- lists.debian.org/debian-lts-announce/2026/05/msg00017.html (opens in a new tab)