Vulnerability · Published Sep 2, 2026 · Assigned by VulnCheck

CVE-2026-82522libjxl < 0.12.0 Container Box Parser Integer Underflow via 32-bit Size Truncation

Medium 5.4

In plain English

A medium-severity security flaw in libjxl from libjxl. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 35% of all known vulnerabilities).

Severity (CVSS 3.1)5.4Medium

Exploit odds (30 days)0.4%top 64.8% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official description

libjxl before 0.12 contains an integer underflow vulnerability in the container box parser that allows remote attackers to inject arbitrary metadata by exploiting 64-bit box size truncation to size_t on 32-bit platforms. Attackers can supply a crafted JPEG XL file causing the decoder to parse attacker-controlled codestream bytes as phantom box headers, enabling injection of arbitrary metadata (Exif, XMP, IPTC, JUMBF) and potential out-of-bounds reads.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
Debian:12	jpeg-xl	no fix listed	DEBIAN-CVE-2026-82522
Debian:13	jpeg-xl	no fix listed	DEBIAN-CVE-2026-82522
Debian:14	jpeg-xl	no fix listed	DEBIAN-CVE-2026-82522
Ubuntu:24.04:LTS	jpeg-xl	no fix listed	UBUNTU-CVE-2026-82522
Ubuntu:26.04:LTS	jpeg-xl	no fix listed	UBUNTU-CVE-2026-82522
Ubuntu:26.10	jpeg-xl	no fix listed	UBUNTU-CVE-2026-82522

Affected products (as reported)

Vendor	Product	Versions
libjxl	libjxl	0 – before 0.12.0

Weakness: CWE-681 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N

References

Release Notes release-notes
Pull Request issue-tracking
Patch Commit patch
https://www.vulncheck.com/advisories/libjxl-container-box-parser-integer-underflow-via-32-bit-size-truncation third-party-advisory