CVE-2026-51807: Stack Overflow (CVSS 9.8)

Description

Heap-based out-of-bounds write in j2k_precinct_subband::parse_packet_header() in OpenHTJ2K versions 0.18.3 and earlier (fixed in v0.18.4) caused by missing bounds validation before coding-pass lengths are written to j2k_codeblock::pass_length[128]. A crafted JPEG 2000 codestream containing malformed PPM packet headers can trigger a heap-based out-of-bounds write in j2k_precinct_subband::parse_packet_header() in source/core/coding/coding_units.cpp due to missing bounds validation for the j2k_codeblock::pass_length[128] array which can lead to heap corruption and process termination.

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CVSS v3.1 Score

9.8

CRITICAL

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

EPSS — Exploit Prediction

0.0037

Probability of exploitation

0.29%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-121 CWE-121

References

Other References

https://github.com/osamu620/OpenHTJ2K/blob/main/CHANGELOG https://github.com/osamu620/OpenHTJ2K/commit/0778b93 https://github.com/osamu620/OpenHTJ2K/compare/0778b93...v0.18.4 https://github.com/osamu620/OpenHTJ2K/releases

Frequently Asked Questions

What is CVE-2026-51807? +

Heap-based out-of-bounds write in j2k_precinct_subband::parse_packet_header() in OpenHTJ2K versions 0.18.3 and earlier (fixed in v0.18.4) caused by missing bounds validation before coding-pass lengths are written to j2k_codeblock::pass_length[128]. A crafted JPEG 2000 codestream containing malformed PPM packet headers can trigger a heap-based out-of-bounds write in j2k_precinct_subband::parse_packet_header() in source/core/coding/coding_units.cpp due to missing bounds validation for the j2k_codeblock::pass_length[128] array which can lead to heap corruption and process termination. It has a CVSS v3.1 base score of 9.8 (CRITICAL).

How severe is CVE-2026-51807? +

CVE-2026-51807 has a CVSS v3.1 score of 9.8 out of 10, rated CRITICAL. This is a critical vulnerability that should be patched immediately. The EPSS score is 0.0037, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-51807? +

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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