---
title: "CVE-2026-43515: Apache Tomcat - Security constraints not correctly applied"
url: https://erroneo.us/security/cve/CVE-2026-43515/
description: "CVE-2026-43515 (org.apache.tomcat.embed:tomcat-embed-core (Maven)): Improper Authorization vulnerability when multiple method constraints define an HTTP…"
type: vulnerability-record
section: "Security Digest"
date_published: 2026-05-12
date_modified: 2026-06-04
publisher: erroneo.us
author: erroneo.us Security Desk
cve: "CVE-2026-43515"
kev: false
cvss: 9.1
epss: 0.01221
license: All rights reserved. Quote with attribution and a link.
---

# CVE-2026-43515: Apache Tomcat - Security constraints not correctly applied

**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 1.2% , percentile 68: FIRST’s model estimates a 1.2% chance of exploitation activity in the next 30 days, higher than 68% 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

Improper Authorization vulnerability when multiple method constraints define an HTTP method for the same extension 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 7.0.0 through 7.0.109. 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: 9.1 `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N`
- GitHub CVSS 3.1: 9.1 `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N`

## 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): 1.22% probability of exploitation activity in the next 30 days; percentile 68.

## Sources

- [lists.apache.org](https://lists.apache.org/thread/746nxfxod0wsocxtmv8pb8nkgmwpc6bb)
- [GitHub Advisory GHSA-5m62-pw8w-7w9f](https://github.com/advisories/GHSA-5m62-pw8w-7w9f)
- [CVE.org record CVE-2026-43515](https://www.cve.org/CVERecord?id=CVE-2026-43515)
- [NVD entry CVE-2026-43515](https://nvd.nist.gov/vuln/detail/CVE-2026-43515)
- [openwall.com](http://www.openwall.com/lists/oss-security/2026/05/12/11)
- [github.com](https://github.com/apache/tomcat/commit/276087d9c7abbcecc6c4fb4e4b08cf64780c6e36)
- [github.com](https://github.com/apache/tomcat/commit/c621317382682206fb58ab92ebd3e1b6fdd10ce9)
- [github.com](https://github.com/apache/tomcat/commit/db919ff9912b4d61d1b702a1342b8bde39270031)
- [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-2026-43515/ · Security Digest: https://erroneo.us/security/ · More: https://erroneo.us/llms.txt