CVE-2026-55955: Org.apache.tomcat:tomcat: Apache Tomcat has an Improper Authentication vulnerability
Affects org.apache.tomcat:tomcatSource GCVE Database
Not known to be exploited · CVSS 6.5 Medium : upgrade to 11.0.23 when convenient.
Data as of 4 Nov 2026, 17:15 UTC
- Patch
- Available – fixed in 11.0.23, 10.1.56, 9.0.119
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:NExploitation evidence
Disclosed: evidence found.
CVE published 29 Jun 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 4 Nov 2026.
What to do
Upgrade org.apache.tomcat:tomcat and org.apache.tomcat:tomcat-tribes to 11.0.23; org.apache.tomcat:tomcat and org.apache.tomcat:tomcat-tribes to 10.1.56; org.apache.tomcat:tomcat and org.apache.tomcat:tomcat-tribes to 9.0.119.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| Mavenorg.apache.tomcat:tomcat | Affected
| Fixed in
|
| Mavenorg.apache.tomcat:tomcat | Affected
| Fixed in
|
| Mavenorg.apache.tomcat:tomcat | Affected
| Fixed in
|
| Mavenorg.apache.tomcat:tomcat | Affected
| Fixed in– |
| Mavenorg.apache.tomcat:tomcat | Affected
| Fixed in– |
| Mavenorg.apache.tomcat:tomcat-tribes | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
Users should upgrade affected Apache Tomcat versions to 11.0.23, 10.1.56, or 9.0.119 where the vulnerability is fixed. Applying these official patches fully mitigates the issue.
Description
Apache Tomcat contains an improper authentication vulnerability (CVE-2026-55955) affecting multiple versions from 7.0.100 through 11.0.22. This flaw allows a replay attack against the EncryptionInterceptor in the cluster component. The issue is fixed in versions 11.0.23, 10.1.56, and 9.0.119.
References
- nvd.nist.gov/vuln/detail/CVE-2026-55955 (opens in a new tab)
- github.com/apache/tomcat/commit/3a9ff01d2dfaca651edacbda3260e37b98b540d3 (opens in a new tab)
- github.com/apache/tomcat/commit/5e594400c7f6ac0eaf2526bd64442a70f5ccaace (opens in a new tab)
- github.com/apache/tomcat/commit/6a7a432cd7fb4ef358dc12e8da99cf3ab320f3fe (opens in a new tab)
- github.com/apache/tomcat (opens in a new tab)
- lists.apache.org/thread/g4p5sf45p3f9r011pwqs9r54yd64s106 (opens in a new tab)
- tomcat.apache.org/security-10.html (opens in a new tab)
- tomcat.apache.org/security-11.html (opens in a new tab)
- tomcat.apache.org/security-9.html (opens in a new tab)
- openwall.com/lists/oss-security/2026/06/29/24 (opens in a new tab)