CVE-2026-51807
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedHeap-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.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · high confidenceHeap-based out-of-bounds write vulnerability in OpenHTJ2K's j2k_precinct_subband::parse_packet_header() function. The function writes coding-pass lengths to a fixed 128-element array (j2k_codeblock::pass_length[128]) without validating bounds, allowing a crafted JPEG 2000 codestream with malformed PPM packet headers to write beyond array boundaries, causing heap corruption.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Identify OpenHTJ2K library presenceSearch for the OpenHTJ2K library file (typically named libopenhtj2k.so, openhtj2k.dll, or similar) in system library directories or application bundles. Also check for linked dependencies in applications that handle JPEG 2000 images.Affected if OpenHTJ2K library is found on the system or embedded in applications
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Determine OpenHTJ2K versionRun 'strings' or inspect library metadata to find the version string. Check library file properties, or if source code is available, look for version tags in the repository. Compare against the fixed version 0.18.4.Affected if The installed version is earlier than 0.18.4 or version cannot be determined
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Verify JPEG 2000 processing capabilityIdentify applications or tools that process JPEG 2000 images. Check if these applications link against OpenHTJ2K using 'ldd' on Linux or dependency walkers on Windows.Affected if Applications that parse JPEG 2000 codestreams are using OpenHTJ2K version below 0.18.4
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Inspect PPM marker parsingSince the vulnerability is triggered by malformed PPM (Packet Packet Marker) headers in JPEG 2000 codestreams, examine if the environment processes user-supplied or untrusted JPEG 2000 files. Check logs or debug output for JPEG 2000 parsing activity.Affected if The environment parses JPEG 2000 images, particularly those that may contain PPM markers, using a vulnerable OpenHTJ2K version
A user is affected if OpenHTJ2K version 0.18.4 or later is NOT installed and the system processes JPEG 2000 images using this library.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
From vendor dataUpgrade OpenHTJ2K to version 0.18.4 or later. Since this is a library vulnerability, all applications using the affected library version should be rebuilt with the patched version.
- Consultation3.0 h
- Implementation2.0 h
- Testing4.0 h
- Review / QA2.0 h
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Free · runs locallyCheck whether your project pulls in CVE-2026-51807 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2026-51807 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Version or environment caveats, and links to real fixes
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