CVE-2026-34757
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).
Does this matter?
Lower severity and a low EPSS score (0.19%). Track it; it rarely justifies an emergency change on its own.
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.
- CVSS 3.1
- 4.4 MEDIUMCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N
- EPSS
- 0.19% probability · 9th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-416
- Affected
- libpng/libpng · debian/debian linux
- Source
- security-advisories@github.com
EPSS 0.2% since 26 October 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
References
- https://github.com/pnggroup/libpng/commit/398cbe3df03f4e11bb031e07f416dfdde3684e8aPatch
- https://github.com/pnggroup/libpng/commit/55d20aaa322c9274491cda82c5cd4f99b48c6bccPatch
- https://github.com/pnggroup/libpng/issues/836Exploit, Issue Tracking, Mitigation
- https://github.com/pnggroup/libpng/issues/837Exploit, Issue Tracking, Mitigation
- https://github.com/pnggroup/libpng/security/advisories/GHSA-6fr7-g8h7-v645Mitigation, Patch, Vendor Advisory
- https://lists.debian.org/debian-lts-announce/2026/05/msg00017.htmlMailing List, Third Party Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.