CVE-2026-51807
Remote code execution via buffer overflow in OpenHTJ2K j2k parser.
Is CVE-2026-51807 being exploited?
Not confirmed. CVE-2026-51807 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked. EPSS currently estimates a 0.67% probability of exploitation in the next 30 days.
How severe is CVE-2026-51807?
CVE-2026-51807 is rated Critical with a CVSS score of 9.8. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2026-51807?
Yes. A fix has been recorded for CVE-2026-51807. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-51807 affect?
CVE-2026-51807 affects OpenHTJ2K <= 0.18.4, Applications linking OpenHTJ2K for JPEG2000 decoding, Servers/processes that parse untrusted .j2k images, Client applications that open malicious j2k files. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-51807?
Upgrade OpenHTJ2K to a patched release (>0.18.4) or block/unpack untrusted j2k files
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Remote arbitrary code execution by processing crafted JPEG2000 (.j2k) data, enabling full system compromise of apps that decode attacker-controlled images.
Immediate action required