CVE-2026-43512: Apache Tomcat Apache Tomcat - Digest Authenticator Vulnerability

CRITICAL
Advisory Identifier: GHSA-h6fc-48rj-7qqh
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CVSS 9.8
CWE-287
Published
Advisory Summary

CVE-2026-43512 is a CRITICAL (CVSS 9.8) apache tomcat - digest authenticator vulnerability (CWE-287: Improper Authentication) affecting Apache Tomcat libraries in the Maven ecosystem. The issue involves apache tomcat - digest authenticator will authenticate any unknown user. Remediation is available by upgrading affected packages to version 9.0.118, 10.1.55, 11.0.22.

CVE-2026-43512 at a Glance

CVE Identifier CVE-2026-43512
GHSA Identifier GHSA-h6fc-48rj-7qqh
Severity CRITICAL
CVSS v3.1 Base Score 9.8
CWE Classification CWE-287: Improper Authentication
Affected Product Apache Tomcat
Package Ecosystem Maven
Published Date
Last Updated

Security Impact

CVSS: 9.8

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H).

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required None (PR:N)
User Interaction None (UI:N)
Scope Unchanged (S:U)
Confidentiality High (C:H)
Integrity High (I:H)
Availability High (A:H)

How to Fix CVE-2026-43512

To remediate this vulnerability, upgrade all affected Apache Tomcat dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

org.apache.tomcat.embed:tomcat-embed-core fixed: 9.0.118 
<dependency>
    <groupId>org.apache.tomcat.embed</groupId>
    <artifactId>tomcat-embed-core</artifactId>
    <version>9.0.118</version>
</dependency>
org.apache.tomcat.embed:tomcat-embed-core fixed: 10.1.55 
<dependency>
    <groupId>org.apache.tomcat.embed</groupId>
    <artifactId>tomcat-embed-core</artifactId>
    <version>10.1.55</version>
</dependency>
org.apache.tomcat.embed:tomcat-embed-core fixed: 11.0.22 
<dependency>
    <groupId>org.apache.tomcat.embed</groupId>
    <artifactId>tomcat-embed-core</artifactId>
    <version>11.0.22</version>
</dependency>
org.apache.tomcat:tomcat fixed: 9.0.118 
<dependency>
    <groupId>org.apache.tomcat</groupId>
    <artifactId>tomcat</artifactId>
    <version>9.0.118</version>
</dependency>
org.apache.tomcat:tomcat fixed: 10.1.55 
<dependency>
    <groupId>org.apache.tomcat</groupId>
    <artifactId>tomcat</artifactId>
    <version>10.1.55</version>
</dependency>
org.apache.tomcat:tomcat fixed: 11.0.22 
<dependency>
    <groupId>org.apache.tomcat</groupId>
    <artifactId>tomcat</artifactId>
    <version>11.0.22</version>
</dependency>
org.apache.tomcat:tomcat-catalina fixed: 9.0.118 
<dependency>
    <groupId>org.apache.tomcat</groupId>
    <artifactId>tomcat-catalina</artifactId>
    <version>9.0.118</version>
</dependency>
org.apache.tomcat:tomcat-catalina fixed: 10.1.55 
<dependency>
    <groupId>org.apache.tomcat</groupId>
    <artifactId>tomcat-catalina</artifactId>
    <version>10.1.55</version>
</dependency>
org.apache.tomcat:tomcat-catalina fixed: 11.0.22 
<dependency>
    <groupId>org.apache.tomcat</groupId>
    <artifactId>tomcat-catalina</artifactId>
    <version>11.0.22</version>
</dependency>
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

mvn dependency:tree -Dincludes=org.apache.tomcat.embed

How to Check if You Are Affected

To determine whether your Java application is affected by CVE-2026-43512, inspect your build dependencies using the Maven Dependency Plugin:

mvn dependency:tree -Dincludes=org.apache.tomcat.embed

Analyze the terminal output to locate any version of Apache Tomcat in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 9.0.118), your application is affected.

Note: The mvn dependency:tree -Dincludes=org.apache.tomcat.embed command inspects the resolved dependency graph declared in your project's POM files; it does not perform automated security scanning or inspect runtime dynamic classpaths. Always verify runtime container classpaths and shaded JARs.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-287: Improper Authentication, where when an actor claims to have a given identity, the product does not prove or insufficiently proves that the claim is correct. In Apache Tomcat, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

Versions Affected: Apache Tomcat 11.0.0-M1 to 11.0.21 Apache Tomcat 10.1.0-M1 to 10.1.54 Apache Tomcat 9.0.0.M1 to 9.0.117 Older, unsupported versions may also be affected Description: When DIGEST authentication was configured, any user not known to the configured Realm would be authenticated if they presented the password "null". Mitigation: Users of the affected versions should apply one of the following mitigations: - Upgrade to Apache Tomcat 11.0.22 or later - Upgrade to Apache Tomcat 10.1.55 or later - Upgrade to Apache Tomcat 9.0.118 or later

CVE-2026-43512 Affected Apache Tomcat Versions

9 component(s)
Fixed Versions:
9.0.11810.1.5511.0.22
Product / Package Ecosystem Affected Versions Fixed Version
org.apache.tomcat.embed:tomcat-embed-core
maven/org.apache.tomcat.embed/tomcat-embed-core
Maven
< 9.0.118
9.0.118
org.apache.tomcat.embed:tomcat-embed-core
maven/org.apache.tomcat.embed/tomcat-embed-core
Maven
≥ 10.1.0-M1
< 10.1.55
10.1.55
org.apache.tomcat.embed:tomcat-embed-core
maven/org.apache.tomcat.embed/tomcat-embed-core
Maven
≥ 11.0.0-M1
< 11.0.22
11.0.22
org.apache.tomcat:tomcat
maven/org.apache.tomcat/tomcat
Maven
< 9.0.118
9.0.118
org.apache.tomcat:tomcat
maven/org.apache.tomcat/tomcat
Maven
< 10.1.55
≥ 10.1.0-M1
10.1.55
org.apache.tomcat:tomcat
maven/org.apache.tomcat/tomcat
Maven
≥ 11.0.0-M1
< 11.0.22
11.0.22
org.apache.tomcat:tomcat-catalina
maven/org.apache.tomcat/tomcat-catalina
Maven
< 9.0.118
9.0.118
org.apache.tomcat:tomcat-catalina
maven/org.apache.tomcat/tomcat-catalina
Maven
≥ 10.1.0-M1
< 10.1.55
10.1.55
org.apache.tomcat:tomcat-catalina
maven/org.apache.tomcat/tomcat-catalina
Maven
≥ 11.0.0-M1
< 11.0.22
11.0.22

References

NVD — CVE-2026-43512 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-43512
Security Fix Commit FIX COMMIT
https://github.com/apache/tomcat/commit/3d4d3fae07a6cd9c2eb193c5491001740ec64448
Security Fix Commit FIX COMMIT
https://github.com/apache/tomcat/commit/6565a6cb6499e56fe2f34457cec99f9d1c4f39e9
Security Fix Commit FIX COMMIT
https://github.com/apache/tomcat/commit/a99c355e8199adbfd67c9a1fffbd85b810b196cd
lists.apache.org/thread/7x09x7o12sol... WEB
https://lists.apache.org/thread/7x09x7o12solvclslw3sz0288xc8wx73
Apache Tomcat Security Information SECURITY
https://tomcat.apache.org/security-10.html
Apache Tomcat Security Information SECURITY
https://tomcat.apache.org/security-11.html
Apache Tomcat Security Information SECURITY
https://tomcat.apache.org/security-9.html
Apache Tomcat Security Information SECURITY
http://www.openwall.com/lists/oss-security/2026/05/12/8

Frequently Asked Questions

What is CVE-2026-43512?
CVE-2026-43512 is a security vulnerability in Apache Tomcat involving Apache Tomcat - Digest authenticator will authenticate any unknown user under CWE-287: Improper Authentication.
Which Apache Tomcat versions are affected?
Affected versions include releases prior to 9.0.118, 10.1.55, 11.0.22 across affected packages: org.apache.tomcat.embed:tomcat-embed-core, org.apache.tomcat:tomcat, org.apache.tomcat:tomcat-catalina.
What version fixes CVE-2026-43512?
Upgrading to 9.0.118, 10.1.55, 11.0.22 (or the latest patched release for your respective branch) resolves the vulnerability.
Is tomcat-embed-core affected?
Yes, org.apache.tomcat.embed:tomcat-embed-core is affected in releases prior to 9.0.118, 10.1.55, 11.0.22. Upgrade your dependency to 9.0.118, 10.1.55, 11.0.22 or later.
Is tomcat affected?
Yes, org.apache.tomcat:tomcat is affected in releases prior to 9.0.118, 10.1.55, 11.0.22. Upgrade your dependency to 9.0.118, 10.1.55, 11.0.22 or later.
What is the CVSS score of CVE-2026-43512?
CVE-2026-43512 has a CVSS v3.1 base score of 9.8 (CRITICAL) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.
What CWE is associated with CVE-2026-43512?
CVE-2026-43512 is classified under CWE-287: Improper Authentication (When an actor claims to have a given identity, the product does not prove or insufficiently proves that the claim is correct.).
How can I check Maven dependencies for CVE-2026-43512?
Run the dependency tree command: 'mvn dependency:tree -Dincludes=org.apache.tomcat.embed'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-h6fc-48rj-7qqh",
  "modified" : "2026-05-18T20:38:28Z",
  "published" : "2026-05-12T18:30:38Z",
  "aliases" : [ "CVE-2026-43512" ],
  "summary" : "Apache Tomcat - Digest authenticator will authenticate any unknown user",
  "details" : "Versions Affected:\nApache Tomcat 11.0.0-M1 to 11.0.21\nApache Tomcat 10.1.0-M1 to 10.1.54\nApache Tomcat 9.0.0.M1 to 9.0.117\nOlder, unsupported versions may also be affected\n\nDescription:\nWhen DIGEST authentication was configured, any user not known to the\nconfigured Realm would be authenticated if they presented the password\n\"null\".\n\nMitigation:\nUsers of the affected versions should apply one of the following\nmitigations:\n- Upgrade to Apache Tomcat 11.0.22 or later\n- Upgrade to Apache Tomcat 10.1.55 or later\n- Upgrade to Apache Tomcat 9.0.118 or later",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Maven",
      "name" : "org.apache.tomcat.embed:tomcat-embed-core"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "9.0.118"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Maven",
      "name" : "org.apache.tomcat.embed:tomcat-embed-core"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "10.1.0-M1"
      }, {
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      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Maven",
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    },
    "ranges" : [ {
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        "fixed" : "11.0.22"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Maven",
      "name" : "org.apache.tomcat:tomcat"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
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      }, {
        "fixed" : "9.0.118"
      } ]
    } ]
  }, {
    "package" : {
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      "name" : "org.apache.tomcat:tomcat"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "10.1.0-M1"
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      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Maven",
      "name" : "org.apache.tomcat:tomcat"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "11.0.0-M1"
      }, {
        "fixed" : "11.0.22"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Maven",
      "name" : "org.apache.tomcat:tomcat-catalina"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "9.0.118"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Maven",
      "name" : "org.apache.tomcat:tomcat-catalina"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "10.1.0-M1"
      }, {
        "fixed" : "10.1.55"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Maven",
      "name" : "org.apache.tomcat:tomcat-catalina"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "11.0.0-M1"
      }, {
        "fixed" : "11.0.22"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-43512"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/apache/tomcat/commit/3d4d3fae07a6cd9c2eb193c5491001740ec64448"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/apache/tomcat/commit/6565a6cb6499e56fe2f34457cec99f9d1c4f39e9"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/apache/tomcat/commit/a99c355e8199adbfd67c9a1fffbd85b810b196cd"
  }, {
    "type" : "WEB",
    "url" : "https://lists.apache.org/thread/7x09x7o12solvclslw3sz0288xc8wx73"
  }, {
    "type" : "WEB",
    "url" : "https://tomcat.apache.org/security-10.html"
  }, {
    "type" : "WEB",
    "url" : "https://tomcat.apache.org/security-11.html"
  }, {
    "type" : "WEB",
    "url" : "https://tomcat.apache.org/security-9.html"
  }, {
    "type" : "WEB",
    "url" : "http://www.openwall.com/lists/oss-security/2026/05/12/8"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-287" ],
    "severity" : "CRITICAL",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-05-18T20:38:27Z",
    "nvd_published_at" : "2026-05-12T16:16:17Z"
  }
}