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Fencer Vulns
high 8.8

CVE-2026-1837 json

libjxl: Out-of-bounds write in grayscale color transformation when using LCMS2

published 2026-02-11 8 mo ago modified 2026-07-15 3 mo ago also EUVD-2026-6177

cvss
8.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 25%
public exploits
0
none known

Summary

A specially-crafted file can cause libjxl's decoder to write pixel data to uninitialized unallocated memory. Soon after that data from another uninitialized unallocated region is copied to pixel data.

This can be done by requesting color transformation of grayscale images to another grayscale color space. Buffers allocated for 1-float-per-pixel are used as if they are allocated for 3-float-per-pixel. That happens only if LCMS2 is used as CMS engine. There is another CMS engine available (selected by build flags).

Patch / fix

  • libjxl_project libjxl 0.9.5, 0.10.5, 0.11.2
  • jpeg-xl Debian 13 0.11.2-0.1~deb13u1
  • jpeg-xl Debian 14 0.11.2-0.1

debian advisories DEBIAN-CVE-2026-1837

  • jpeg-xl Ubuntu 25.10 0.11.1-6ubuntu1.1

ubuntu advisories UBUNTU-CVE-2026-1837

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

  • libjxl SLES for SAP applications 16.0, SLES 16.0 0.11.2-160000.1.1
  • libjxl SLE Module for Package Hub 15 SP7 0.10.3-150700.4.6.1

suse advisories SUSE-SU-2026:20903-1SUSE-SU-2026:0648-1

  • libjxl openSUSE Leap 16.0 0.11.2-160000.1.1
  • libjxl openSUSE Tumbleweed 0.11.2-1.1

opensuse advisories openSUSE-SU-2026:20385-1openSUSE-SU-2026:10271-1

  • libjxl Alpine 3.23 0.11.2-r0

alpine advisories ALPINE-CVE-2026-1837

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

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-2026-1837 updated cvss 8.8

libjxl: libjxl: Out-of-bounds write in grayscale color transformation when using LCMS2

  • Red Hat Enterprise Linux 7 firefox Red Hat Enterprise Linux 8 firefox, thunderbird Red Hat Enterprise Linux 9 firefox, firefox-x11, thunderbird Red Hat Enterprise Linux 10 firefox, thunderbird
    not affected: vulnerable code not present

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
8 mo ago

Exploit prediction

0.33% chance of exploitation in the next 30 days, higher than 25% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/libjxl/libjxl/issues/4549 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 4.0 8.7 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
CISA ADP 3.1 8.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
CNA 4.0 8.7 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
NVD 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CNA 3.1 8.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Affected products

  • Google libjxl
  • Red Hat Red Hat Enterprise Linux 10
  • Red Hat Red Hat Enterprise Linux 7
  • Red Hat Red Hat Enterprise Linux 8
  • Red Hat Red Hat Enterprise Linux 9

Classification

Weakness
  • CWE-805 Buffer Access with Incorrect Length Value
  • CWE-787 Out-of-bounds Write
  • CWE-770 Allocation of Resources Without Limits or Throttling

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.