CVE-2026-34757

Name: CVE-2026-34757
Creator: NVD / NIST
Published: 2026-04-09T15:16:11.003+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 4.4/10EPSS 0.19%

Last modified Jun 17, 2026

CVE-2026-34757 is a medium-severity vulnerability rated 4.4/10 on the CVSS scale. 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. EPSS estimates a 0.19% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.1

4.4/10

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N

EPSS Probability

0.19%

9.4th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-416

Affected Software

Vendor	Product	Versions
Libpng	Libpng	>= 1.0.9, < 1.6.57
Debian	Debian Linux	11.0

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

Timeline

Published: Apr 9, 2026
Last Modified: Jun 17, 2026
Status: Analyzed

Frequently Asked Questions

What is CVE-2026-34757?

How severe is CVE-2026-34757?

CVE-2026-34757 has a CVSS score of 4.4/10 (MEDIUM severity). The EPSS model estimates a 0.19% probability of exploitation in the next 30 days.

How do I fix CVE-2026-34757?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2026-34757?

Run a free Strix scan to check your systems for this vulnerability.

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Source: NVD / NIST