Vulnerability 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 Score
MEDIUM
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Libpng | Libpng | >= 1.0.9, < 1.6.57 |
| Debian | Debian Linux | 11.0 |
Related Weaknesses (CWE)
References
- https://github.com/pnggroup/libpng/commit/398cbe3df03f4e11bb031e07f416dfdde3684ePatch
- https://github.com/pnggroup/libpng/commit/55d20aaa322c9274491cda82c5cd4f99b48c6bPatch
- https://github.com/pnggroup/libpng/issues/836ExploitIssue TrackingMitigation
- https://github.com/pnggroup/libpng/issues/837ExploitIssue TrackingMitigation
- https://github.com/pnggroup/libpng/security/advisories/GHSA-6fr7-g8h7-v645MitigationPatchVendor Advisory
- https://lists.debian.org/debian-lts-announce/2026/05/msg00017.htmlMailing ListThird Party Advisory
FAQ
What is CVE-2026-34757?
CVE-2026-34757 is a vulnerability with a CVSS score of 5.1 (MEDIUM). 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...
How severe is CVE-2026-34757?
CVE-2026-34757 has been rated MEDIUM with a CVSS base score of 5.1/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-34757?
Check the references section above for vendor advisories and patch information. Affected products include: Libpng Libpng, Debian Debian Linux.