# 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 CVE-2026-34757 is fixed in 12 products on 1 platform, first by libpng-tools 1.6.34-1ubuntu0.18.04.2+esm3, released April 9, 2026. It is not reported as exploited. Patch Radar priority: Routine. - Web page: https://patchblox.com/security/cve/CVE-2026-34757 - Priority: Routine - CVSS: 5.1 (Moderate) - EPSS: 0.0020 - CISA KEV: not listed - Exploited (vendor report): no - Publicly disclosed: no - Published: Apr 9, 2026 - Weakness: Use After Free - Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-34757 ## 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. ## Where it's fixed | Platform | Product | Fixed in | Fix | Released | |---|---|---|---|---| | Linux | libpng amzn 2023 | 2:1.6.37-10.amzn2023.0.13 | [ALAS2023-2026-1670](https://patchblox.com/security/data/fix/linux/alas2023-2026-1670.md) | May 11, 2026 | | Linux | libpng-debuginfo amzn 2023 | 2:1.6.37-10.amzn2023.0.13 | [ALAS2023-2026-1670](https://patchblox.com/security/data/fix/linux/alas2023-2026-1670.md) | May 11, 2026 | | Linux | libpng-debugsource amzn 2023 | 2:1.6.37-10.amzn2023.0.13 | [ALAS2023-2026-1670](https://patchblox.com/security/data/fix/linux/alas2023-2026-1670.md) | May 11, 2026 | | Linux | libpng-devel amzn 2023 | 2:1.6.37-10.amzn2023.0.13 | [ALAS2023-2026-1670](https://patchblox.com/security/data/fix/linux/alas2023-2026-1670.md) | May 11, 2026 | | Linux | libpng-devel-debuginfo amzn 2023 | 2:1.6.37-10.amzn2023.0.13 | [ALAS2023-2026-1670](https://patchblox.com/security/data/fix/linux/alas2023-2026-1670.md) | May 11, 2026 | | Linux | libpng-static amzn 2023 | 2:1.6.37-10.amzn2023.0.13 | [ALAS2023-2026-1670](https://patchblox.com/security/data/fix/linux/alas2023-2026-1670.md) | May 11, 2026 | | Linux | libpng-tools Ubuntu 18.04.6 LTS (bionic) | 1.6.34-1ubuntu0.18.04.2+esm3 | [libpng-tools 1.6.34-1ubuntu0.18.04.2+esm3](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-libpng-tools-1.6.34-1ubuntu0.18.04.2-esm3.md) | Apr 9, 2026 | | Linux | libpng-tools Ubuntu 20.04 LTS (focal) | 1.6.37-2ubuntu0.1~esm3 | [libpng-tools 1.6.37-2ubuntu0.1~esm3](https://patchblox.com/security/data/fix/linux/ubuntu-focal-libpng-tools-1.6.37-2ubuntu0.1-esm3.md) | Jun 4, 2026 | | Linux | libpng-tools Ubuntu 22.04.1 LTS (jammy) | 1.6.37-3ubuntu0.5 | [libpng-tools 1.6.37-3ubuntu0.5](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-libpng-tools-1.6.37-3ubuntu0.5.md) | Apr 9, 2026 | | Linux | libpng-tools Ubuntu 24.04.5 LTS (noble) | 1.6.43-5ubuntu0.6 | [libpng-tools 1.6.43-5ubuntu0.6](https://patchblox.com/security/data/fix/linux/ubuntu-noble-libpng-tools-1.6.43-5ubuntu0.6.md) | Apr 9, 2026 | | Linux | libpng-tools Ubuntu 25.10 (questing) | 1.6.50-1ubuntu0.5 | [libpng-tools 1.6.50-1ubuntu0.5](https://patchblox.com/security/data/fix/linux/ubuntu-questing-libpng-tools-1.6.50-1ubuntu0.5.md) | Apr 9, 2026 | | Linux | libpng-tools amzn 2023 | 2:1.6.37-10.amzn2023.0.13 | [ALAS2023-2026-1670](https://patchblox.com/security/data/fix/linux/alas2023-2026-1670.md) | May 11, 2026 | | Linux | libpng-tools-debuginfo amzn 2023 | 2:1.6.37-10.amzn2023.0.13 | [ALAS2023-2026-1670](https://patchblox.com/security/data/fix/linux/alas2023-2026-1670.md) | May 11, 2026 | | Linux | libpng1.6 Debian 12.15 (bookworm) | 1.6.39-2+deb12u5 | [DEBIAN-CVE-2026-34757](https://patchblox.com/security/data/fix/linux/debian-cve-2026-34757.md) | Apr 9, 2026 | | Linux | libpng1.6 Debian 13.5 (trixie) | 1.6.48-1+deb13u5 | [DEBIAN-CVE-2026-34757](https://patchblox.com/security/data/fix/linux/debian-cve-2026-34757.md) | Apr 9, 2026 | | Linux | libpng1.6 Debian 14 | 1.6.57-1 | [DEBIAN-CVE-2026-34757](https://patchblox.com/security/data/fix/linux/debian-cve-2026-34757.md) | Apr 9, 2026 | | Linux | libpng16 opensuse-leap 16.0 | 1.6.44-160000.7.1 | [OPENSUSE-SU-2026:20593-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-20593-1.md) | Apr 21, 2026 | | Linux | libpng16 sles 15.7 | 1.6.40-150600.3.20.1 | [SUSE-SU-2026:1602-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-1602-1.md) | Apr 24, 2026 | | Linux | libpng16-16 Ubuntu 18.04.6 LTS (bionic) | 1.6.34-1ubuntu0.18.04.2+esm3 | [libpng16-16 1.6.34-1ubuntu0.18.04.2+esm3](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-libpng16-16-1.6.34-1ubuntu0.18.04.2-esm3.md) | Apr 9, 2026 | | Linux | libpng16-16 Ubuntu 20.04 LTS (focal) | 1.6.37-2ubuntu0.1~esm3 | [libpng16-16 1.6.37-2ubuntu0.1~esm3](https://patchblox.com/security/data/fix/linux/ubuntu-focal-libpng16-16-1.6.37-2ubuntu0.1-esm3.md) | Jun 4, 2026 | | Linux | libpng16-16 Ubuntu 22.04.1 LTS (jammy) | 1.6.37-3ubuntu0.5 | [libpng16-16 1.6.37-3ubuntu0.5](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-libpng16-16-1.6.37-3ubuntu0.5.md) | Apr 9, 2026 | | Linux | libpng16-16t64 Ubuntu 24.04.5 LTS (noble) | 1.6.43-5ubuntu0.6 | [libpng16-16t64 1.6.43-5ubuntu0.6](https://patchblox.com/security/data/fix/linux/ubuntu-noble-libpng16-16t64-1.6.43-5ubuntu0.6.md) | Apr 9, 2026 | | Linux | libpng16-16t64 Ubuntu 25.10 (questing) | 1.6.50-1ubuntu0.5 | [libpng16-16t64 1.6.50-1ubuntu0.5](https://patchblox.com/security/data/fix/linux/ubuntu-questing-libpng16-16t64-1.6.50-1ubuntu0.5.md) | Apr 9, 2026 | --- Data as of 2026-11-08T13:06:02Z UTC. 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