---
id: CVE-2026-1837
title: >-
  A specially-crafted file can cause libjxl's decoder to write pixel data to
  uninitialized unallocated memory
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 colo…
severity: high
cvss: 7.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'
cwe:
  - CWE-805
  - CWE-770
  - CWE-787
vendor: libjxl_project
product: libjxl
affected:
  - 'libjxl >= 0.9.0, <= 0.11.1'
published: '2026-02-11'
updated: '2026-06-30'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-1837'
references:
  - url: 'https://github.com/libjxl/libjxl/issues/4549'
    label: cve-coordination@google.com
  - url: 'https://access.redhat.com/security/cve/CVE-2026-1837'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2438974'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://github.com/libjxl/libjxl/issues/4549'
    label: 134c704f-9b21-4f2e-91b3-4a467353bcc0
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-1837.json
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
tags:
  - nvd
epss: 0.00286
epssPercentile: 0.1877
ingestedAt: '2026-07-03T18:53:52.198Z'
---

## Overview

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).

## Affected

- `libjxl >= 0.9.0, <= 0.11.1`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.