Security readout for executives and security teams
Plain-English summary
OpenHTJ2K versions 0.18.4 and earlier are reported vulnerable to a critical buffer overflow in decoder code. If an organization uses this library to process untrusted HTJ2K/JPEG 2000 content, a successful attack could allow arbitrary code execution with major confidentiality, integrity, and availability impact.
Executive priority
Prioritize this as urgent for any environment processing untrusted images with OpenHTJ2K. Business risk is high because the reported impact includes arbitrary code execution and full CIA compromise. If OpenHTJ2K is not used, risk is limited to monitoring and documentation.
Technical view
CVE-2026-51808 is a CWE-120 buffer overflow in OpenHTJ2K decoder.cpp, specifically openhtj2k_decoder_impl invoke-related functions. The CVSS 3.1 score is 9.8 with network attack vector, low complexity, no privileges, and no user interaction. The public record lists affected metadata as n/a, limiting asset-matching precision.
Likely exposure
Likely exposure is applications, services, or pipelines that embed OpenHTJ2K 0.18.4 or earlier and decode externally supplied image content. CPE and vendor/product fields are not populated, so dependency inventory is the practical exposure source.
Exploitation context
The CVSS vector indicates remote, low-complexity exploitation without authentication or user interaction. The source bundle does not show CISA KEV listing or any cited evidence of active exploitation. Treat exploitation status as unconfirmed, not absent.
Researcher notes
Evidence is strongest for vulnerability type, location, severity, and affected version range from the CVE description. Public metadata is incomplete for vendor/product/CPE mapping. Do not claim exploitation in the wild without additional sourced evidence.
Mitigation direction
- Identify any direct or transitive OpenHTJ2K dependency.
- Check OpenHTJ2K changelog, PR #320, and v0.18.5 release guidance.
- Prioritize vendor-recommended fixed release if running 0.18.4 or earlier.
- Restrict untrusted image decoding paths until remediation is complete.
- Monitor CVE and project references for corrected affected-version details.
Validation and detection
- Search SBOMs and build manifests for OpenHTJ2K usage.
- Confirm deployed OpenHTJ2K versions are not 0.18.4 or earlier.
- Review services that decode externally supplied HTJ2K/JPEG 2000 files.
- Verify remediation against vendor release notes or changelog.
- Document unknowns where CPE metadata is unavailable.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-120: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupExecution behavior lookup
The CVE wording references code or command execution, so execution technique review may help defensive triage. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2026-51808 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Critical
- CVSS
- 9.8 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
SSVC decision data
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H3.95.9CISA-ADPVulnerability scoring details
Base CVSS 3.1 score
9.8CriticalVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Vulnerability timeline
Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.
- CVE reservedCVE Program
The CVE ID was reserved by the assigning CNA.
- CVE publishedCVE Program
The CVE record was published.
- CVE updatedCVE Program
The CVE record metadata indicates this as the latest update time.
ADP provider summaries
Source materials
- CVE List V5 sourceCVE List V5
- https://github.com/osamu620/OpenHTJ2K/blob/main/CHANGELOGCVE reference, mitre
- https://github.com/osamu620/OpenHTJ2K/pull/320CVE reference, mitre
- https://github.com/osamu620/OpenHTJ2K/releases/tag/v0.18.5CVE reference, mitre
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')
Buffer Copy without Checking Size of Input ('Classic Buffer Overflow') represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.