# CVE-2026-120252: imagecodecs 2023.1.23 through 2026.10.10 Stack Buffer Overflow via jpegsof3_decode()

Status: published. Published: 2026-11-01. Updated: 2026-11-02.

imagecodecs 2023.1.23 through 2026.10.10 contains a stack-based buffer overflow vulnerability in the lossless JPEG Define Huffman Table parser in decode_jpegsof3(). Attackers can supply a crafted lossless JPEG whose DHT symbol counts wrap an 8-bit sum, overflowing the 32-entry HufVal and HufSz stack arrays and crashing the calling process.

## Remediation

No remediation reported in collected sources

## Affected products and versions

- cgohlke / imagecodecs (imagecodecs): ≥ 2023.1.23; ≤ 2026.10.10 (affected, custom). Source: CNA: VulnCheck

## Severity and prioritization

- CVSS 4.0: 6.8 (medium); CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N; source: CNA: VulnCheck

- CVSS 3.1: 5.5 (medium); CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H; source: CNA: VulnCheck

- CVSS 4.0: 6.8 (medium); CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/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; source: NVD: disclosure@vulncheck.com

- CVSS 3.1: 5.5 (medium); CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H; source: NVD: disclosure@vulncheck.com

- CISA KEV: No listing in collected sources

- EPSS: 0.14% as of 2026-11-02; percentile 3.06%

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

- Weaknesses: CWE-121

## Exploit evidence

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

## References

- https://github.com/cgohlke/imagecodecs/issues/157 (CNA: VulnCheck; issue-tracking)

- https://github.com/cgohlke/imagecodecs/blob/v2026.10.10/3rdparty/jpegsof3/jpegsof3.cpp#L394 (CNA: VulnCheck; technical-description)

- https://github.com/cgohlke/imagecodecs (CNA: VulnCheck; product)

- https://www.vulncheck.com/advisories/imagecodecs-2023.1.23-through-2026.10.10-stack-buffer-overflow-via-jpegsof3-decode (CNA: VulnCheck; third-party-advisory)

- https://github.com/cgohlke/imagecodecs (disclosure@vulncheck.com)

- https://github.com/cgohlke/imagecodecs/blob/v2026.10.10/3rdparty/jpegsof3/jpegsof3.cpp#L394 (disclosure@vulncheck.com)

- https://github.com/cgohlke/imagecodecs/issues/157 (disclosure@vulncheck.com)

- https://www.vulncheck.com/advisories/imagecodecs-2023.1.23-through-2026.10.10-stack-buffer-overflow-via-jpegsof3-decode (disclosure@vulncheck.com)

## Provenance

- CNA: VulnCheck: https://www.cve.org/CVERecord?id=CVE-2026-120252; retrieved 2026-11-02; source updated 2026-11-02

- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-120252; retrieved 2026-11-02; source updated 2026-11-01

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2026-120252; retrieved 2026-11-02; source updated Not reported

Revision: 65eca6c5e48c1d6267935797ba60cb60fe0062cc4d7ea8ca4d784371a6283b6a

Canonical: https://y2.dev/cve/CVE-2026-120252

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Collected public records only. Check source status for coverage and freshness.