CVE-2026-43512

CRITICAL LAB

Apache Tomcat: Digest authenticator will authenticate any unknown user

Title source: cna
STIX 2.1

Exploitation Summary

EIP tracks 1 public exploit for CVE-2026-43512. PoCs published by covepseng.

AI-analyzed exploit summary This repository contains a functional exploit for CVE-2026-43512, an authentication bypass vulnerability in Apache Tomcat's DIGEST authentication. The exploit leverages a bug in RealmBase.getDigest() where a null password is converted to the string 'null', allowing authentication with a non-existent username and the literal password 'null'.

Description

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.

Exploits (1)

github WORKING POC
by covepseng · gopoc
https://github.com/covepseng/cve-2026-43512-poc

This repository contains a functional exploit for CVE-2026-43512, an authentication bypass vulnerability in Apache Tomcat's DIGEST authentication. The exploit leverages a bug in RealmBase.getDigest() where a null password is converted to the string 'null', allowing authentication with a non-existent username and the literal password 'null'.

Classification
Working Poc 95%
Attack Type
Auth Bypass
Complexity
Moderate
Reliability
Reliable
Target: Apache Tomcat (versions prior to 9.0.118)
No auth needed
Prerequisites: Tomcat server with DIGEST authentication enabled · Protected resource requiring authentication
mistral-large-3 · analyzed Jun 09, 2026 Full analysis →

References (2)

Core 2

Scores

CVSS v3 9.8
EPSS 0.0123
EPSS Percentile 65.5%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CISA SSVC

Vulnrichment
Exploitation none
Automatable yes
Technical Impact total

Lab Environment

COMMUNITY
Community Lab
docker pull tomcat:11.0.0-M1-jdk11

Details

CWE
CWE-592
Status published
Products (16)
apache/tomcat 7.0.0 - 7.0.109
Apache Software Foundation/Apache Tomcat < 7.0.0
Apache Software Foundation/Apache Tomcat 10.1.0-M1 - 10.1.54
Apache Software Foundation/Apache Tomcat 11.0.0-M1 - 11.0.21
Apache Software Foundation/Apache Tomcat 7.0.0 - 7.0.109
Apache Software Foundation/Apache Tomcat 8.5.0 - 8.5.100
Apache Software Foundation/Apache Tomcat 9.0.0.M1 - 9.0.117
org.apache.tomcat/tomcat 0 - 9.0.118Maven
org.apache.tomcat/tomcat 10.1.0-M1 - 10.1.55Maven
org.apache.tomcat/tomcat 11.0.0-M1 - 11.0.22Maven
... and 6 more
Published May 12, 2026
Tracked Since May 12, 2026