SOC status:Duty analyst on shift

UK Cyber Defence
VulnerabilityDeferred

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].

CRITICAL 9.8EPSS 0.67%

Does this matter?

High impact if exploited, but EPSS currently rates exploitation as unlikely (0.67%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.

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.

CVSS 3.1
9.8 CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS
0.67% probability · 50th percentile
CISA KEV
Not listed
Weakness
CWE-121
Source
cve@mitre.org

Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.