CVE-2026-120252: Stack Overflow (CVSS 5.5)

Description

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.

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CVSS v3.1 Score

5.5

MEDIUM

CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H

Weakness Type (CWE)

CWE-121 CWE-121

References

Other References

https://github.com/cgohlke/imagecodecs https://github.com/cgohlke/imagecodecs/blob/v2026.10.10/3rdparty/jpegsof3/jpegsof3.cpp#L394 https://github.com/cgohlke/imagecodecs/issues/157 https://www.vulncheck.com/advisories/imagecodecs-2023.1.23-through-2026.10.10-stack-buffer-overflow-via-jpegsof3-decode

Frequently Asked Questions

What is CVE-2026-120252? +

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. It has a CVSS v3.1 base score of 5.5 (MEDIUM).

How severe is CVE-2026-120252? +

CVE-2026-120252 has a CVSS v3.1 score of 5.5 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance.

How do I check if I'm vulnerable to CVE-2026-120252? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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CVE-2026-120252