{"id":"CVE-2026-51807","title":"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_l…","summary":"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_l…","severity":"critical","cvss":9.8,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","cwe":["CWE-121"],"published":"2026-07-14","updated":"2026-07-17","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-51807","references":[{"url":"https://github.com/osamu620/OpenHTJ2K/blob/main/CHANGELOG","label":"cve@mitre.org"},{"url":"https://github.com/osamu620/OpenHTJ2K/commit/0778b93","label":"cve@mitre.org"},{"url":"https://github.com/osamu620/OpenHTJ2K/compare/0778b93...v0.18.4","label":"cve@mitre.org"},{"url":"https://github.com/osamu620/OpenHTJ2K/releases","label":"cve@mitre.org"}],"tags":["nvd"],"epss":0.00671,"epssPercentile":0.50631,"ingestedAt":"2026-07-18T14:23:38.116Z","slug":"CVE-2026-51807","body":"## Overview\n\nHeap-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.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"midnight","depthScore":54,"depthScoreParts":{"impact":53.9,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}