dbcve.org
TomcatWeb server / proxy · Apache

CVE-2026-55276

CRITICAL · 9.1 CVSS v3.1 Published 2026-06-29
Fix available
A fix is available. Upgrade to 9.0.119 / 10.1.56 or later.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable No privileges Zero-click 8 weeks old

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
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.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

An Always-Incorrect Control Flow Implementation vulnerability in Apache Tomcat causes the logged effective web.xml configuration to omit special roles and empty authorization constraints. This means security-sensitive configuration details are missing from logs that administrators rely on for security auditing and visibility into the application's actual security posture.

MitigationUpgrade Apache Tomcat to version 11.0.23, 10.1.56, or 9.0.119 to obtain the fix for this logging discrepancy.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
TomcatWeb server / proxy
Affected:< 9.0.119>= 10.1.0, < 10.1.56>= 11.0.0, < 11.0.23

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Find Tomcat installation directory
    Locate the Tomcat home directory (check $CATALINA_HOME environment variable, or common locations like /opt/tomcat, /usr/share/tomcat, /var/lib/tomcat, or on Windows: C:\Program Files\Apache Software Foundation\Tomcat)
    Affected if Apache Tomcat is installed on the system
  2. Determine installed Tomcat version
    Run the version script: on Unix/Linux execute {tomcat-home}/bin/version.sh, on Windows execute {tomcat-home}\bin\version.bat. Alternatively, check {tomcat-home}/RELEASE-NOTES file or the ServerInfo.properties inside catalina.jar in the lib directory
    Affected if Unable to determine version or version is within the vulnerable range
  3. Compare against affected version ranges
    Check if the installed version falls into any of these vulnerable ranges: version < 9.0.119; OR version >= 10.1.0 AND < 10.1.56; OR version >= 11.0.0 AND < 11.0.23
    Affected if Installed version matches one of these ranges

You are affected if your Apache Tomcat version is 9.0.x below 9.0.119, 10.1.x below 10.1.56, or 11.0.x below 11.0.23 - in these versions the web.xml configuration logging omits special roles and empty authorization constraints.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 9.0.119 / 10.1.56 / 11.0.23 or later
Fixed in 9.0.11910.1.5611.0.23
Interim mitigation

Upgrade Apache Tomcat to version 11.0.23, 10.1.56, or 9.0.119 to obtain the fix for this logging discrepancy.

Recommended fix High confidence

9.0.119 (for Tomcat 9.x) or 10.1.56 (for Tomcat 10.1.x) or 11.0.23 (for Tomcat 11.x)

  1. 1. Identify current Apache Tomcat version by checking the $CATALINA_HOME/README file or the server info page
  2. 2. Stop the Tomcat service/instance
  3. 3. Create a complete backup of the current Tomcat installation directory including conf/ and webapps/ directories
  4. 4. Download the appropriate fixed Tomcat version: 9.0.119, 10.1.56, or 11.0.23 from the Apache Tomcat downloads page (tomcat.apache.org)
  5. 5. Extract the new Tomcat version to a temporary location
  6. 6. Copy the conf/ directory from the old installation to preserve custom configurations, or migrate settings manually
  7. 7. Redeploy web applications from the backup to the new installation
  8. 8. Start the Tomcat service and verify startup completes without errors
Caveat Review Apache Tomcat migration notes for your upgrade path; minor version jumps typically have minimal breaking changes but always test in non-production first

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Tomcat Scoped from the published advisory
  • Consultation1.0 h
  • Implementation2.0 h
  • Testing1.0 h
  • Review / QA1.0 h
5.0 hours of engineering $890
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,424.

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-55276 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data