---
title: "CVE-2026-43512: Apache Tomcat - Digest authenticator will authenticate any unknown user"
url: https://erroneo.us/security/cve/CVE-2026-43512/
description: "CVE-2026-43512 (org.apache.tomcat.embed:tomcat-embed-core (Maven)): DEPRECATED: Authentication Bypass Issues vulnerability in digest authentication in…"
type: vulnerability-record
section: "Security Digest"
date_published: 2026-05-12
date_modified: 2026-05-18
publisher: erroneo.us
author: erroneo.us Security Desk
cve: "CVE-2026-43512"
kev: false
cvss: 9.8
epss: 0.01326
license: All rights reserved. Quote with attribution and a link.
---

# CVE-2026-43512: Apache Tomcat - Digest authenticator will authenticate any unknown user

**Signal:** Critical and remotely reachable. No known exploitation yet, but it is network-reachable without credentials. (Computed from CISA KEV, EPSS and CVSS; not an editorial verdict.)

## Should you act?

- No confirmed exploitation. It is not in CISA’s KEV catalog and CISA’s SSVC assessment records no known exploitation. That can change quickly after a public write-up; re-check if you are affected.
- EPSS 1.3% , percentile 71: FIRST’s model estimates a 1.3% chance of exploitation activity in the next 30 days, higher than 71% of all scored CVEs (moderate). EPSS is a probability, not a verdict.
- Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
- Only applies if your dependency tree includes org.apache.tomcat.embed:tomcat-embed-core (Maven) < 9.0.118, fixed in 9.0.118 ; org.apache.tomcat.embed:tomcat-embed-core (Maven) >= 10.1.0-M1, < 10.1.55, fixed in 10.1.55 ; org.apache.tomcat.embed:tomcat-embed-core (Maven) >= 11.0.0-M1, < 11.0.22, fixed in 11.0.22 ; org.apache.tomcat:tomcat (Maven) < 9.0.118, fixed in 9.0.118 . Check your lockfile, including transitive dependencies.

## What it is

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.

## Affected packages

- Maven `org.apache.tomcat.embed:tomcat-embed-core` < 9.0.118 → fixed: 9.0.118
- Maven `org.apache.tomcat.embed:tomcat-embed-core` >= 10.1.0-M1, < 10.1.55 → fixed: 10.1.55
- Maven `org.apache.tomcat.embed:tomcat-embed-core` >= 11.0.0-M1, < 11.0.22 → fixed: 11.0.22
- Maven `org.apache.tomcat:tomcat` < 9.0.118 → fixed: 9.0.118
- Maven `org.apache.tomcat:tomcat` >= 10.1.0-M1, < 10.1.55 → fixed: 10.1.55
- Maven `org.apache.tomcat:tomcat` >= 11.0.0-M1, < 11.0.22 → fixed: 11.0.22
- Maven `org.apache.tomcat:tomcat-catalina` < 9.0.118 → fixed: 9.0.118
- Maven `org.apache.tomcat:tomcat-catalina` >= 10.1.0-M1, < 10.1.55 → fixed: 10.1.55
- Maven `org.apache.tomcat:tomcat-catalina` >= 11.0.0-M1, < 11.0.22 → fixed: 11.0.22

## Affected products (CVE record)

- Apache Software Foundation Apache Tomcat: 11.0.0-M1 <= 11.0.21, 10.1.0-M1 <= 10.1.54, 9.0.0.M1 <= 9.0.117, 8.5.0 <= 8.5.100, 7.0.0 <= 7.0.109

## Severity

- CISA-ADP CVSS 3.1: 9.8 `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`
- GitHub CVSS 3.1: 9.8 `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`

## Exploitation

- CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
- CISA SSVC assessment: exploitation none , automatable yes , technical impact total .
- FIRST EPSS (model of 2026-10-21): 1.33% probability of exploitation activity in the next 30 days; percentile 71.

## Sources

- [lists.apache.org](https://lists.apache.org/thread/7x09x7o12solvclslw3sz0288xc8wx73)
- [GitHub Advisory GHSA-h6fc-48rj-7qqh](https://github.com/advisories/GHSA-h6fc-48rj-7qqh)
- [CVE.org record CVE-2026-43512](https://www.cve.org/CVERecord?id=CVE-2026-43512)
- [NVD entry CVE-2026-43512](https://nvd.nist.gov/vuln/detail/CVE-2026-43512)
- [openwall.com](http://www.openwall.com/lists/oss-security/2026/05/12/8)
- [github.com](https://github.com/apache/tomcat/commit/3d4d3fae07a6cd9c2eb193c5491001740ec64448)
- [github.com](https://github.com/apache/tomcat/commit/6565a6cb6499e56fe2f34457cec99f9d1c4f39e9)
- [github.com](https://github.com/apache/tomcat/commit/a99c355e8199adbfd67c9a1fffbd85b810b196cd)
- [tomcat.apache.org](https://tomcat.apache.org/security-10.html)
- [tomcat.apache.org](https://tomcat.apache.org/security-11.html)
- [tomcat.apache.org](https://tomcat.apache.org/security-9.html)

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Source page: https://erroneo.us/security/cve/CVE-2026-43512/ · Security Digest: https://erroneo.us/security/ · More: https://erroneo.us/llms.txt