Tomcat6: Always-Incorrect Control Flow Implementation vulnerability
Affects tomcat6Source GCVE Database
Not known to be exploited · CVSS 9.1 Critical · fixed in 8.0.32-1ubuntu1.13+esm2 : patch tomcat6 as a priority.
Data as of 26 Oct 2026, 13:47 UTC
- EPSS
- 0.6% chance of exploitation in 30 days – higher than 48% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 8.0.32-1ubuntu1.13+esm2, 8.5.39-1ubuntu1~18.04.3+esm6
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:NExploitation evidence
Disclosed: evidence found.
CVE published 29 Jun 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: 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 26 Oct 2026.
What to do
Upgrade the Ubuntu tomcat8 to 8.0.32-1ubuntu1.13+esm2 (package) or 8.5.39-1ubuntu1~18.04.3+esm6 (package).
Patches and advisories
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 26.10tomcat10pkg:deb/ubuntu/tomcat10?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Ubuntu 26.10tomcat11pkg:deb/ubuntu/tomcat11?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Ubuntu 26.10tomcat9pkg:deb/ubuntu/tomcat9?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTStomcat10pkg:deb/ubuntu/tomcat10?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTStomcat9pkg:deb/ubuntu/tomcat9?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTStomcat11pkg:deb/ubuntu/tomcat11?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
Description
Always-Incorrect Control Flow Implementation vulnerability in Apache Tomcat meant that special roles and empty authorisation constraints were not included when the effective web.xml was logged. This issue affects Apache Tomcat: from 11.0.0-M1 through 11.0.22, from 10.1.0-M1 through 10.1.55, from 9.0.0.M1 through 9.0.118, from 8.5.0 through 8.5.100. Other versions that have reached end of support may also be affected. Users are recommended to upgrade to version 11.0.23, 10.1.56 or 9.0.119 which fixes the issue.
References
- ubuntu.com/security/CVE-2026-55276 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-55276 (opens in a new tab)
- github.com/apache/tomcat/commit/f844614c6d92eeb11e81e179606bf4c390f642dd (opens in a new tab)
- github.com/apache/tomcat/commit/e391c6b201eae2ad9707a1335aff68ab8b3e0f84 (opens in a new tab)
- github.com/apache/tomcat/commit/25677f90fd721c26ef0f613d34ef8275b1aafc31 (opens in a new tab)
- github.com/apache/tomcat/commit/17daf80a738d66a8e6cad05c5e32c2db81500ce1 (opens in a new tab)
- github.com/apache/tomcat/commit/3ca8cae5fd3796b1bd9759e11b0e238161e7a39c (opens in a new tab)
- lists.apache.org/thread/jy09xjlzn6r2qwvqoph8vcmf959yq68v (opens in a new tab)
- openwall.com/lists/oss-security/2026/06/29/23 (opens in a new tab)
- ubuntu.com/security/notices/USN-8551-1 (opens in a new tab)