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TomcatWeb server / proxy · Apache

CVE-2026-43512

CRITICAL · 9.8 CVSS v3.1 Published 2026-05-12
Fix available
A fix is available. Upgrade to 9.0.118 / 10.1.55 or later.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable No privileges Zero-click

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
DEPRECATED: Authentication Bypass Issues vulnerability in digest authentication in Apache Tomcat. This issue affects Apache Tomcat: from 11.0.0-M1 through 11.0.21, from 10.1.0-M1 through 10.1.54, from 9.0.0.M1 through 9.0.117, from 8.5.0 through 8.5.100, from before 7.0.0. Older unsupported versions any also be affect Users are recommended to upgrade to version 11.0.22, 10.1.55 or 9.0.118 which fix 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

Authentication bypass vulnerability in HTTP digest authentication mechanism in Apache Tomcat allows unauthenticated attackers to bypass authentication checks. The vulnerability affects digest authentication implementation across multiple Tomcat versions.

MitigationUpgrade Apache Tomcat to version 11.0.22, 10.1.55, or 9.0.118 (or later) to resolve the digest authentication bypass. If upgrade is not immediately possible, disable digest authentication and use alternative authentication methods.

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:>= 7.0.0, <= 7.0.109>= 8.5.0, <= 8.5.100>= 9.0.0, < 9.0.118>= 10.1.0, < 10.1.55>= 11.0.0, < 11.0.22

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
High

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

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. Identify installed Tomcat version
    Check the RELEASE-NOTE file in the Tomcat home directory, or run 'version.sh' (or 'version.bat' on Windows) from the bin directory. The output will display the Tomcat version number.
    Affected if The installed version falls within 7.0.0-7.0.109, 8.5.0-8.5.100, 9.0.0-9.0.117, 10.1.0-10.1.54, or 11.0.0-11.0.21.
  2. Locate digest authentication configuration
    Search for 'DigestAuthenticator' in conf/server.xml, conf/context.xml, or in the web application's WEB-INF/web.xml file. Also check for 'authenticator' valve definitions with digest-related settings.
    Affected if A DigestAuthenticator valve or digest authentication configuration is found in any of these configuration files.
  3. Verify vulnerable authentication method is in use
    Examine the web.xml file for your web application (either in conf/web.xml or in WEB-INF/web.xml of your application). Look for <auth-method>DIGEST</auth-method> within a <security-constraint> element.
    Affected if The web application is configured to use DIGEST as the authentication method.
  4. Check for realm configuration supporting digest
    Review the realm configuration in server.xml. Look for <Realm> elements (such as MemoryRealm, DataSourceRealm, or UserDatabaseRealm) that are positioned above or within the same Host as the DigestAuthenticator.
    Affected if A realm is configured and the DigestAuthenticator is enabled, meaning Tomcat is using digest-based authentication.

You are affected if your Tomcat version is within the vulnerable ranges AND digest authentication (DIGEST) is configured as the authentication method in your web application or server configuration.

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 9.0.118 / 10.1.55 / 11.0.22 or later
Fixed in 9.0.11810.1.5511.0.22
Interim mitigation

Upgrade Apache Tomcat to version 11.0.22, 10.1.55, or 9.0.118 (or later) to resolve the digest authentication bypass. If upgrade is not immediately possible, disable digest authentication and use alternative authentication methods.

Recommended fix High confidence

Tomcat 9.0.118 (or 10.1.55 or 11.0.22 depending on your major version line)

  1. 1. Identify the currently installed Apache Tomcat version by checking the server's startup logs or the RELEASE-NOTES file in the Tomcat directory
  2. 2. For Tomcat 9.x users: Upgrade to Tomcat 9.0.118 or later (e.g., download from https://tomcat.apache.org/download-90.cgi)
  3. 3. For Tomcat 10.1.x users: Upgrade to Tomcat 10.1.55 or later (e.g., download from https://tomcat.apache.org/download-101.cgi)
  4. 4. For Tomcat 11.x users: Upgrade to Tomcat 11.0.22 or later (e.g., download from https://tomcat.apache.org/download-110.cgi)
  5. 5. Replace the existing Tomcat installation files with the new version, preserving your existing configuration files (server.xml, context.xml, etc.)
  6. 6. Restart the Tomcat service and verify the application functions correctly
  7. 7. Verify the fix by reviewing the Tomcat release notes for version 9.0.118, 10.1.55, or 11.0.22 to confirm the digest authentication vulnerability is resolved
Caveat Major version upgrades (e.g., 9.x to 10.x or 10.x to 11.x) may require application code changes due to javax to jakarta namespace migration; minor version upgrades within the same major version should be largely compatible

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

Fix this in Tomcat Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing12.0 h
  • Review / QA4.0 h
28.0 hours of engineering $4,760
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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-2026-43512 in production — separate from our analysis above.

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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
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  • Version or environment caveats, and links to real fixes
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