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

Status: published. Published: 2026-09-02. Updated: 2026-11-08.

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.

## Remediation

- fix: The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches. (source: CNA: VulnCheck) — https://github.com/libjxl/libjxl/pull/4885
- fix: The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches. (source: CNA: VulnCheck) — https://github.com/libjxl/libjxl/commit/22ad80af1454f0444ea34115e49ed40517147d68

## Affected products and versions

- libjxl / libjxl (libjxl/libjxl): ≥ 0; < 0.12.0 (affected, semver). Source: CNA: VulnCheck

## Severity and prioritization

- CVSS 4.0: 5.3 (medium); CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N; source: CNA: VulnCheck

- CVSS 3.1: 5.4 (medium); CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N; source: CNA: VulnCheck

- CISA KEV: No listing in collected sources

- EPSS: 0.41% as of 2026-11-08; percentile 35.27%

- SSVC: exploitation none; automatable no; technical impact partial; source ADP: CISA-ADP

- Weaknesses: CWE-681

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://github.com/libjxl/libjxl/releases/tag/v0.12.0 (CNA: VulnCheck; release-notes)

- https://github.com/libjxl/libjxl/pull/4885 (CNA: VulnCheck; issue-tracking, patch)

- https://github.com/libjxl/libjxl/commit/22ad80af1454f0444ea34115e49ed40517147d68 (CNA: VulnCheck; patch)

- https://www.vulncheck.com/advisories/libjxl-container-box-parser-integer-underflow-via-32-bit-size-truncation (CNA: VulnCheck; third-party-advisory)

## Provenance

- CNA: VulnCheck: https://www.cve.org/CVERecord?id=CVE-2026-82522; retrieved 2026-11-08; source updated 2026-11-08

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2026-82522; retrieved 2026-11-08; source updated Not reported

Revision: ac1b0e5d7c84fdd86ba2c0144cc04438f6584f32ac394f0dc60b6dcddbc69d2a

Canonical: https://y2.dev/cve/CVE-2026-82522

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