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Fencer Vulns
high 7.5

CVE-2026-33416 json

LIBPNG has use-after-free via pointer aliasing in `png_set_tRNS` and `png_set_PLTE`

published 2026-03-26 7 mo ago modified 2026-07-18 3 mo ago also EUVD-2026-16258 , JLSEC-2026-95

cvss
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
1.1%
EPSS 1.1% chance of exploitation in 30 days, percentile 65%
public exploits
0
none known

Summary

LIBPNG is a reference library for use in applications that read, create, and manipulate PNG (Portable Network Graphics) raster image files. In versions 1.2.1 through 1.6.55, `png_set_tRNS` and `png_set_PLTE` each alias a heap-allocated buffer between `png_struct` and `png_info`, sharing a single allocation across two structs with independent lifetimes. The `trans_alpha` aliasing has been present since at least libpng 1.0, and the `palette` aliasing since at least 1.2.1. Both affect all prior release lines `png_set_tRNS` sets `png_ptr->trans_alpha = info_ptr->trans_alpha` (256-byte buffer) and `png_set_PLTE` sets `info_ptr->palette = png_ptr->palette` (768-byte buffer). In both cases, calling `png_free_data` (with `PNG_FREE_TRNS` or `PNG_FREE_PLTE`) frees the buffer through `info_ptr` while the corresponding `png_ptr` pointer remains dangling. Subsequent row-transform functions dereference and, in some code paths, write to the freed memory. A second call to `png_set_tRNS` or `png_set_PLTE` has the same effect, because both functions call `png_free_data` internally before reallocating the `info_ptr` buffer. Version 1.6.56 fixes the issue.

Patch / fix

  • julia libpng_jll 1.6.56+0
  • libpng libpng 1.6.56
  • libpng1.6 Debian 12 1.6.39-2+deb12u4
  • libpng1.6 Debian 13 1.6.48-1+deb13u4
  • libpng1.6 Debian 14 1.6.56-1

debian advisories DEBIAN-CVE-2026-33416

  • libpng1.6 Ubuntu 22.04 LTS 1.6.37-3ubuntu0.5
  • libpng1.6 Ubuntu 24.04 LTS 1.6.43-5ubuntu0.6
  • libpng1.6 Ubuntu 25.10 1.6.50-1ubuntu0.5
  • libpng Ubuntu Pro 14.04 LTS 1.2.50-1ubuntu2.14.04.3+esm2
  • libpng Ubuntu Pro 16.04 LTS 1.2.54-1ubuntu1.1+esm3
  • libpng1.6 Ubuntu Pro 16.04 LTS 1.6.20-2ubuntu0.1~esm4
  • libpng1.6 Ubuntu Pro 18.04 LTS 1.6.34-1ubuntu0.18.04.2+esm3
  • libpng1.6 Ubuntu Pro 20.04 LTS 1.6.37-2ubuntu0.1~esm3

ubuntu advisories UBUNTU-CVE-2026-33416

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • libpng hummingbird 1 1.6.58-2.1.hum1
  • libpng-tools hummingbird 1 1.6.58-2.1.hum1
  • libpng RHEL 8 2:1.6.34-11.el8_10
  • libpng RHEL 9 2:1.6.37-15.el9_8.2
  • libpng15 RHEL 9 1.5.30-15.el9_8.1
  • libpng RHEL 10.2 2:1.6.40-11.el10_2.1
  • libpng15 RHEL 8 1.5.30-9.el8_10
  • libpng12 RHEL 8 1.2.57-7.el8_10

red hat advisories RHSA-2026:80330RHSA-2026:50808RHSA-2026:43702RHSA-2026:29901RHSA-2026:29902RHSA-2026:29900

  • libpng16 Linux Micro 6.1 1.6.58-slfo.1.1_1.1
  • libpng16 Linux Micro 6.0 1.6.58-1.1
  • libpng16 SLES for SAP 15 SP6, SLES 15 SP6-LTSS, SLE Module for Basesystem 15 SP7 +1 more 1.6.40-150600.3.17.1
  • libpng16 SLES for SAP 15 SP5, SLES for SAP 15 SP4, SLES 15 SP5-LTSS +9 more 1.6.34-150000.3.22.1
  • libpng16 Linux Micro 6.1 1.6.43-slfo.1.1_4.1
  • libpng16 Linux Micro 6.0 1.6.43-4.1
  • libpng16 SLES 16.0, Linux Micro 6.2, SLES for SAP applications 16.0 1.6.44-160000.6.1
  • libpng15 SLES LTSS Extended Security 12 SP5, SLES 12 SP5-LTSS 1.5.22-10.10.1

suse advisories SUSE-SU-2026:23514-1SUSE-SU-2026:23063-1SUSE-SU-2026:1500-1SUSE-SU-2026:1368-1SUSE-SU-2026:1323-1SUSE-SU-2026:1311-1

  • libpng12 openSUSE Tumbleweed 1.2.59-5.1
  • libpng16 openSUSE Leap 16.0 1.6.44-160000.6.1
  • libpng16 openSUSE Tumbleweed 1.6.56-1.1

opensuse advisories openSUSE-SU-2026:10640-1openSUSE-SU-2026:20466-1openSUSE-SU-2026:10451-1

  • libpng AlmaLinux 8 2:1.6.34-11.el8_10
  • libpng AlmaLinux 10 2:1.6.40-11.el10_2.1
  • libpng15 AlmaLinux 9 1.5.30-15.el9_8.1
  • libpng AlmaLinux 9 2:1.6.37-15.el9_8.2
  • libpng15 AlmaLinux 8 1.5.30-9.el8_10
  • libpng12 AlmaLinux 8 1.2.57-7.el8_10
  • libpng AlmaLinux 9 2:1.6.37-12.el9_7.4
  • libpng AlmaLinux 10 2:1.6.40-8.el10_1.4

almalinux advisories ALSA-2026:29898ALSA-2026:28233ALSA-2026:28244ALSA-2026:28255ALSA-2026:26347ALSA-2026:26348

  • libpng Rocky Linux 8 2:1.6.34-11.el8_10
  • libpng Rocky Linux 10 2:1.6.40-11.el10_2.1
  • libpng15 Rocky Linux 9 1.5.30-15.el9_8.1
  • libpng Rocky Linux 9 2:1.6.37-15.el9_8.2
  • libpng15 Rocky Linux 8 1.5.30-9.el8_10
  • libpng12 Rocky Linux 8 1.2.57-7.el8_10
  • java-25-openjdk Rocky Linux 10 1:25.0.3.0.9-1.el10_1
  • libpng Rocky Linux 10 2:1.6.40-8.el10_1.4

rocky linux advisories RLSA-2026:29898RLSA-2026:28233RLSA-2026:28244RLSA-2026:28255RLSA-2026:26347RLSA-2026:26348

  • libpng Alpine 3.24, Alpine 3.23, Alpine 3.22 +2 more 1.6.56-r0

alpine advisories ALPINE-CVE-2026-33416

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • libpng Azure Linux 3.0 1.6.56-1

azure linux advisories AZL-80990

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-33416 updated cvss 7.5

libpng: libpng: Arbitrary code execution due to use-after-free vulnerability

  • Red Hat build of OpenJDK 1.8 java-17-openjdk, java-21-openjdk, java-21-openjdk-vanilla Red Hat build of OpenJDK 11 ELS java-17-openjdk Red Hat build of OpenJDK 17 java-17-openjdk Red Hat build of OpenJDK 21 java-21-openjdk, java-21-openjdk-vanilla
    affected: workaround, no fix available “To reduce exposure, avoid processing untrusted PNG image files with applications that utilize libpng. Restricting the source of PNG images to trusted origins can limit the attack surface.”
  • Red Hat Enterprise Linux 6 libpng
    affected: workaround, no fix planned “To reduce exposure, avoid processing untrusted PNG image files with applications that utilize libpng. Restricting the source of PNG images to trusted origins can limit the attack surface.”
  • Red Hat Enterprise Linux 8 mingw-libpng, mingw32-libpng, mingw64-libpng
    affected: workaround, no fix available “To reduce exposure, avoid processing untrusted PNG image files with applications that utilize libpng. Restricting the source of PNG images to trusted origins can limit the attack surface.”
  • Red Hat OPENJDK ELS 11.0.31
    fixed: vendor fix “To reduce exposure, avoid processing untrusted PNG image files with applications that utilize libpng. Restricting the source of PNG images to trusted origins can limit the attack surface.” RHSA-2026:9255
  • Red Hat AI Inference Server 3.2 rhaiis/model-opt-cuda-rhel9 1780681984
    fixed: vendor fix “To reduce exposure, avoid processing untrusted PNG image files with applications that utilize libpng. Restricting the source of PNG images to trusted origins can limit the attack surface.” RHSA-2026:25096
  • Red Hat Build of OpenJDK 8u492
    fixed: vendor fix “To reduce exposure, avoid processing untrusted PNG image files with applications that utilize libpng. Restricting the source of PNG images to trusted origins can limit the attack surface.” RHSA-2026:9684
  • Red Hat Build of OpenJDK 17.0.9
    fixed: vendor fix “To reduce exposure, avoid processing untrusted PNG image files with applications that utilize libpng. Restricting the source of PNG images to trusted origins can limit the attack surface.” RHSA-2026:9687
  • Red Hat Build of OpenJDK 21.0.11
    fixed: vendor fix “To reduce exposure, avoid processing untrusted PNG image files with applications that utilize libpng. Restricting the source of PNG images to trusted origins can limit the attack surface.” RHSA-2026:9690
show 18 more
  • Red Hat Build of OpenJDK 25.0.3
    fixed: vendor fix “To reduce exposure, avoid processing untrusted PNG image files with applications that utilize libpng. Restricting the source of PNG images to trusted origins can limit the attack surface.” RHSA-2026:9694
  • Red Hat CodeReady Linux Builder EUS (v.9.4) java-17-openjdk-fastdebug 17.0.19.0.10-1.el9, java-17-openjdk-slowdebug 17.0.19.0.10-1.el9, java-21-openjdk-fastdebug 21.0.11.0.10-1.el9, java-21-openjdk-slowdebug 21.0.11.0.10-1.el9, java-1.8.0-openjdk-fastdebug 1.8.0.492.b09-1.el9, java-1.8.0-openjdk-slowdebug 1.8.0.492.b09-1.el9, +32 more Red Hat CodeReady Linux Builder EUS (v.9.6) java-17-openjdk-fastdebug 17.0.19.0.10-1.el9, java-17-openjdk-slowdebug 17.0.19.0.10-1.el9, java-21-openjdk-fastdebug 21.0.11.0.10-1.el9, java-21-openjdk-slowdebug 21.0.11.0.10-1.el9, java-1.8.0-openjdk-fastdebug 1.8.0.492.b09-1.el9, java-1.8.0-openjdk-slowdebug 1.8.0.492.b09-1.el9, +32 more
    fixed: vendor fix “To reduce exposure, avoid processing untrusted PNG image files with applications that utilize libpng. Restricting the source of PNG images to trusted origins can limit the attack surface.” RHSA-2026:9689
  • Red Hat Discovery 2 discovery/discovery-ui-rhel9 1782756541
    fixed: vendor fix “To reduce exposure, avoid processing untrusted PNG image files with applications that utilize libpng. Restricting the source of PNG images to trusted origins can limit the attack surface.” RHSA-2026:33313
  • Red Hat Enterprise Linux AppStream (v. 8) firefox 140.9.1-1.el8_10, libpng12 1.2.57-7.el8_10, libpng15 1.5.30-9.el8_10, thunderbird 140.9.1-1.el8_10, java-17-openjdk 17.0.19.0.10-1.el8, java-21-openjdk 21.0.11.0.10-1.el8, +21 more Red Hat Enterprise Linux AppStream (v. 9) firefox 140.9.1-1.el9_7, libpng 1.6.37-12.el9_7.4, libpng 1.6.37-15.el9_8.2, libpng15 1.5.30-15.el9_8.1, firefox-x11 140.9.1-1.el9_7, thunderbird 140.9.1-1.el9_7, +31 more Red Hat Enterprise Linux AppStream (v. 10) firefox 140.9.1-1.el10_1, libpng 1.6.40-8.el10_1.4, libpng 1.6.40-11.el10_2.1, thunderbird 140.9.1-1.el10_1, java-25-openjdk 25.0.3.0.9-1.el10_2, java-21-openjdk 21.0.11.0.10-2.el10_2, +15 more
    fixed: vendor fix “To reduce exposure, avoid processing untrusted PNG image files with applications that utilize libpng. Restricting the source of PNG images to trusted origins can limit the attack surface.” RHSA-2026:9689
  • Red Hat Enterprise Linux AppStream AUS (v. 8.2) firefox 140.9.1-1.el8_2, java-1.8.0-openjdk 1.8.0.492.b09-1.el8, java-1.8.0-openjdk-src 1.8.0.492.b09-1.el8, java-1.8.0-openjdk-demo 1.8.0.492.b09-1.el8, java-1.8.0-openjdk-javadoc 1.8.0.492.b09-1.el8, java-1.8.0-openjdk-headless 1.8.0.492.b09-1.el8, +2 more Red Hat Enterprise Linux AppStream AUS (v.8.4) firefox 140.9.1-1.el8_4, libpng12 1.2.57-5.el8_4.2, libpng15 1.5.30-7.el8_4.2, thunderbird 140.9.1-1.el8_4, java-17-openjdk 17.0.19.0.10-1.el8, java-1.8.0-openjdk 1.8.0.492.b09-1.el8, +13 more Red Hat Enterprise Linux AppStream AUS (v.8.6) firefox 140.9.1-1.el8_6, libpng12 1.2.57-5.el8_6.2, libpng15 1.5.30-7.el8_6.2, thunderbird 140.9.1-1.el8_6, java-17-openjdk 17.0.19.0.10-1.el8, java-1.8.0-openjdk 1.8.0.492.b09-1.el8, +13 more Red Hat Enterprise Linux AppStream E4S (v.8.6) firefox 140.9.1-1.el8_6, thunderbird 140.9.1-1.el8_6, java-17-openjdk 17.0.19.0.10-1.el8, java-1.8.0-openjdk 1.8.0.492.b09-1.el8, java-17-openjdk-src 17.0.19.0.10-1.el8, java-17-openjdk-demo 17.0.19.0.10-1.el8, +11 more Red Hat Enterprise Linux AppStream E4S (v.8.8) firefox 140.9.1-1.el8_8, libpng12 1.2.57-5.el8_8.2, libpng15 1.5.30-7.el8_8.2, thunderbird 140.9.1-1.el8_8, java-17-openjdk 17.0.19.0.10-1.el8, java-1.8.0-openjdk 1.8.0.492.b09-1.el8, +13 more Red Hat Enterprise Linux AppStream E4S (v.9.0) firefox 140.9.1-1.el9_0, thunderbird 140.9.1-1.el9_0, java-17-openjdk 17.0.19.0.10-1.el9, java-1.8.0-openjdk 1.8.0.492.b09-1.el9, java-17-openjdk-src 17.0.19.0.10-1.el9, java-17-openjdk-demo 17.0.19.0.10-1.el9, +10 more
    +1 more products
    Red Hat Enterprise Linux AppStream E4S (v.9.2) firefox 140.9.1-1.el9_2, libpng 1.6.37-12.el9_2.4, libpng15 1.5.30-14.el9_2.2, firefox-x11 140.9.1-1.el9_2, thunderbird 140.9.1-1.el9_2, java-17-openjdk 17.0.19.0.10-1.el9, +13 more
    fixed: vendor fix “To reduce exposure, avoid processing untrusted PNG image files with applications that utilize libpng. Restricting the source of PNG images to trusted origins can limit the attack surface.” RHSA-2026:9683
  • Red Hat Enterprise Linux AppStream E4S (v.9.4) libpng15 1.5.30-14.el9_4.2
    fixed: vendor fix “To reduce exposure, avoid processing untrusted PNG image files with applications that utilize libpng. Restricting the source of PNG images to trusted origins can limit the attack surface.” RHSA-2026:28457
  • Red Hat Enterprise Linux AppStream EUS (v. 10.0) firefox 140.9.1-1.el10_0, libpng 1.6.40-8.el10_0.4, thunderbird 140.9.1-1.el10_0, java-21-openjdk 21.0.11.0.10-1.el10_2, java-21-openjdk-src 21.0.11.0.10-1.el10_2, java-21-openjdk-demo 21.0.11.0.10-1.el10_2, +5 more
    fixed: vendor fix “To reduce exposure, avoid processing untrusted PNG image files with applications that utilize libpng. Restricting the source of PNG images to trusted origins can limit the attack surface.” RHSA-2026:13665
  • Red Hat Enterprise Linux AppStream EUS (v.9.4) firefox 140.9.1-1.el9_4, libpng 1.6.37-12.el9_4.4, firefox-x11 140.9.1-1.el9_4, thunderbird 140.9.1-1.el9_4, java-17-openjdk 17.0.19.0.10-1.el9, java-21-openjdk 21.0.11.0.10-1.el9, +20 more Red Hat Enterprise Linux AppStream EUS (v.9.6) firefox 140.9.1-1.el9_6, libpng 1.6.37-12.el9_6.4, libpng15 1.5.30-14.el9_6.2, firefox-x11 140.9.1-1.el9_6, thunderbird 140.9.1-1.el9_6, java-17-openjdk 17.0.19.0.10-1.el9, +21 more
    fixed: vendor fix “To reduce exposure, avoid processing untrusted PNG image files with applications that utilize libpng. Restricting the source of PNG images to trusted origins can limit the attack surface.” RHSA-2026:9689
  • Red Hat Enterprise Linux AppStream EUS EXTENSION (v.8.4) firefox 140.9.1-1.el8_4, libpng12 1.2.57-5.el8_4.2, libpng15 1.5.30-7.el8_4.2, thunderbird 140.9.1-1.el8_4, java-17-openjdk 17.0.19.0.10-1.el8, java-1.8.0-openjdk 1.8.0.492.b09-1.el8, +27 more
    fixed: vendor fix “To reduce exposure, avoid processing untrusted PNG image files with applications that utilize libpng. Restricting the source of PNG images to trusted origins can limit the attack surface.” RHSA-2026:9683
  • Red Hat Enterprise Linux AppStream EUS EXTENSION (v.8.6) libpng12 1.2.57-5.el8_6.2, libpng15 1.5.30-7.el8_6.2
    fixed: vendor fix “To reduce exposure, avoid processing untrusted PNG image files with applications that utilize libpng. Restricting the source of PNG images to trusted origins can limit the attack surface.” RHSA-2026:29020
  • Red Hat Enterprise Linux AppStream TUS (v.8.6) firefox 140.9.1-1.el8_6, thunderbird 140.9.1-1.el8_6, java-17-openjdk 17.0.19.0.10-1.el8, java-1.8.0-openjdk 1.8.0.492.b09-1.el8, java-17-openjdk-src 17.0.19.0.10-1.el8, java-17-openjdk-demo 17.0.19.0.10-1.el8, +11 more Red Hat Enterprise Linux AppStream TUS (v.8.8) firefox 140.9.1-1.el8_8, libpng12 1.2.57-5.el8_8.2, libpng15 1.5.30-7.el8_8.2, thunderbird 140.9.1-1.el8_8, java-17-openjdk 17.0.19.0.10-1.el8, java-1.8.0-openjdk 1.8.0.492.b09-1.el8, +13 more
    fixed: vendor fix “To reduce exposure, avoid processing untrusted PNG image files with applications that utilize libpng. Restricting the source of PNG images to trusted origins can limit the attack surface.” RHSA-2026:9683
  • Red Hat Enterprise Linux BaseOS (v. 8) libpng 1.6.34-11.el8_10
    fixed: vendor fix “To reduce exposure, avoid processing untrusted PNG image files with applications that utilize libpng. Restricting the source of PNG images to trusted origins can limit the attack surface.” RHSA-2026:29898
  • Red Hat Enterprise Linux BaseOS (v. 9) libpng 1.6.37-12.el9_7.4, libpng 1.6.37-15.el9_8.2
    fixed: vendor fix “To reduce exposure, avoid processing untrusted PNG image files with applications that utilize libpng. Restricting the source of PNG images to trusted origins can limit the attack surface.” RHSA-2026:18028
  • Red Hat Enterprise Linux BaseOS (v. 10) libpng 1.6.40-8.el10_1.4, libpng 1.6.40-11.el10_2.1
    fixed: vendor fix “To reduce exposure, avoid processing untrusted PNG image files with applications that utilize libpng. Restricting the source of PNG images to trusted origins can limit the attack surface.” RHSA-2026:18064
  • Red Hat Enterprise Linux BaseOS AUS (v.8.4) libpng 1.6.34-8.el8_4.3
    fixed: vendor fix “To reduce exposure, avoid processing untrusted PNG image files with applications that utilize libpng. Restricting the source of PNG images to trusted origins can limit the attack surface.” RHSA-2026:29902
  • Red Hat Enterprise Linux BaseOS AUS (v.8.6) libpng 1.6.34-8.el8_6.3
    fixed: vendor fix “To reduce exposure, avoid processing untrusted PNG image files with applications that utilize libpng. Restricting the source of PNG images to trusted origins can limit the attack surface.” RHSA-2026:29901
  • Red Hat Enterprise Linux BaseOS E4S (v.8.8) libpng 1.6.34-8.el8_8.3
    fixed: vendor fix “To reduce exposure, avoid processing untrusted PNG image files with applications that utilize libpng. Restricting the source of PNG images to trusted origins can limit the attack surface.” RHSA-2026:29900
  • Red Hat Enterprise Linux BaseOS E4S (v.9.2) libpng 1.6.37-12.el9_2.4
    fixed: vendor fix “To reduce exposure, avoid processing untrusted PNG image files with applications that utilize libpng. Restricting the source of PNG images to trusted origins can limit the attack surface.” RHSA-2026:20550

17 more fixed, 5 more not affected in the full advisory

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
total
Assessed
7 mo ago

Exploit prediction

1.07% chance of exploitation in the next 30 days, higher than 65% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/pnggroup/libpng/pull/824 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 7.5 CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H
OSV 3.1 7.5 CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H

Affected packages

ecosystem package affected fixed in
julia libpng_jll
<1.6.56+0
1.6.56+0

Affected products

  • pnggroup libpng

Classification

Weakness

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.