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
LIBPNG has a yse-after-free in pngsetPLTE, pngsettRNS and pngsethIST leading to corrupted chunk data and potential heap information disclosure
Other sources
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 pnggetPLTE, pnggettRNS, or pnggethIST back into the corresponding setter on the same pngstruct/pnginfo 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.
— MITRE
Affected Software
Remediation
Event History
Frequently Asked Questions
What is the severity of CVE-2026-34757?
CVE-2026-34757 has a high severity rating due to its potential for heap information disclosure.
How do I fix CVE-2026-34757?
To fix CVE-2026-34757, update to the latest version of libpng that patches the vulnerability.
Which versions of libpng are affected by CVE-2026-34757?
CVE-2026-34757 affects libpng versions from 1.0.9 to 1.6.57.
What is the main impact of CVE-2026-34757?
The main impact of CVE-2026-34757 is the potential for corrupted chunk data and information disclosure due to use-after-free vulnerabilities.
Who is the vendor for the affected software in CVE-2026-34757?
The vendor for the affected software in CVE-2026-34757 is Libpng.