CVE-2026-18047

Summary

A flaw was found in Dogtag PKI's ACME responder where the web.xml security constraints use exact URL pattern matching for admin-only enable/disable endpoints. By appending a trailing slash to the URL, an unauthenticated attacker can bypass the Tomcat authentication constraint while RESTEasy still routes the request to the handler, allowing unauthorized toggling of the ACME service state including persistent denial of service.

Affected Software

Weaknesses

• CWE-288: Authentication Bypass Using an Alternate Path or Channel

Workarounds

To mitigate this vulnerability, change the URL patterns in the ACME responder's web.xml from exact-match to prefix-match. Edit the file /usr/share/pki/acme/webapps/acme/WEB-INF/web.xml and replace the url-pattern entries for the enable and disable endpoints:

<url-pattern>/enable</url-pattern> -> <url-pattern>/enable/</url-pattern> <url-pattern>/disable</url-pattern> -> <url-pattern>/disable/</url-pattern>

Then restart the PKI server for the changes to take effect.

ADP Enrichment

CISA ADP Vulnrichment

• SSVC:
• Exploitation: none
  • Automatable: yes
  • Technical Impact: partial

References

• https://access.redhat.com/security/cve/CVE-2026-18047
• https://bugzilla.redhat.com/show_bug.cgi?id=2507956

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