CVE-2026-51807Network attack vector

Heap corruption via unchecked coding-pass count

Published Jul 14, 2026 · Updated Jul 14, 2026

Heap-based out-of-bounds write in OpenHTJ2K 0.18.3 and earlier allows remote attackers to corrupt heap memory via a crafted JPEG 2000 codestream. The parse_packet_header function adds an untrusted segment-pass count to num_passes without ensuring that writes remain within the 128-entry pass_length array. Processing malformed PPM packet headers can terminate the host process; the updated CVE record does not establish arbitrary code execution.

CVSS severity9.8
Critical
EPSS probability0.67%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Heap-based out-of-bounds write in OpenHTJ2K 0.18.3 and earlier allows remote attackers to corrupt heap memory via a crafted JPEG 2000 codestream. The parse_packet_header function adds an untrusted segment-pass count to num_passes without ensuring that writes remain within the 128-entry pass_length array. Processing malformed PPM packet headers can terminate the host process; the updated CVE record does not establish arbitrary code execution.

The record

CVE
CVE-2026-51807
Published
Jul 14, 2026
Updated
Jul 14, 2026
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-121
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 14, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 14, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

9.8CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-121Stack-based Buffer Overflow

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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