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Vulnerabilities

Vulnerability · CVE-2026-15554

the Undertow AJP listener honours forged ssl_cert and is_ssl AJP attributes without requiring any shared-secret authentication.

Published Aug 11, 2026 · catalog updated Oct 15, 2026 · the Undertow AJP listener

Check if you run it

No confirmed exploitation is on record for CVE-2026-15554. EPSS is 0.35%. Act only if a listed version of the Undertow AJP listener is installed.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (the Undertow AJP listener).
  • No version range is stored. A customer cannot check an installed version against this record.
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
High7.4
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.35%
Remediation
Not established
Affected products
See sources for product scope

the Undertow AJP listener honours forged ssl_cert and is_ssl AJP attributes without requiring any shared-secret authentication. This enables an unauthenticated attacker with direct TCP access to port 8009 to bypass CLIENT-CERT authentication by injecting a forged X.509 certificate via the AJP protocol.

No affected version ranges are stored yet. Use the vendor advisory before you decide this record does not apply.

How to fix CVE-2026-15554

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-15554. EPSS is 0.35%. Act only if a listed version of the Undertow AJP listener is installed.

Which versions are affected?

Affected version ranges are not on this record. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-295: Improper Certificate Validation. EPSS 0.35%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

No public source repository is identified for this product.

Timeline

Detection, updates, and resolution for this record.

  1. Aug 11, 2026 · NIST NVD

    Detected

    the Undertow AJP listener honours forged ssl_cert and is_ssl AJP attributes without requiring any shared-secret authentication. This enables an unauthenticated attacker with direct TCP access to port 8009 to bypass CLIENT-CERT authentication by injecting a forged X.509 certificate via the AJP protocol.

  2. Oct 15, 2026 · NIST NVD

    Updated

    the Undertow AJP listener honours forged ssl_cert and is_ssl AJP attributes without requiring any shared-secret authentication. This enables an unauthenticated attacker with direct TCP access to port 8009 to bypass CLIENT-CERT authentication by injecting a forged X.509 certificate via the AJP protocol.

Sources

  • CVE.orgVulnerability recordCVE-2026-15554

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-15554

    30-day exploitation probability 0.4%

    first.org
  • NIST NVDVulnerability recordCVE-2026-15554

    the Undertow AJP listener honours forged ssl_cert and is_ssl AJP attributes without requiring any shared-secret authentication. This enables an unauthenticated attacker with direct TCP access to port 8009 to bypass CLIENT-CERT authentication by injecting a forged X.509 certificat

    nvd.nist.gov

References

Freshness

Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.