# Apache Tomcat Session Fixation vulnerability

Advisory record · `GHSA-23hv-mwm6-g8jf`

- **Identifiers:** `GHSA-23hv-mwm6-g8jf` · `BIT-tomcat-2025-55668` · `CVE-2025-55668`
- **State:** Confirmed
- **Severity:** CVSS 6.5 Medium
- **Critical:** No
- **Weakness (CWE):** [CWE-384](https://cwe.mitre.org/data/definitions/384.html)
- **Tags:** [Authentication bypass](https://agentprime.io/advisories/tag/auth-bypass.md)
- **Published:** 13 Aug 2025
- **Updated:** 1 Jul 2026
- **Reviewed by a person:** No

Published by the GitHub Advisory Database at 13 Aug 2025, 15:30 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

## Affected packages

- `org.apache.tomcat:tomcat-catalina` (Maven): affected `>=11.0.0-M1, <11.0.8 || >=10.1.0-M1, <10.1.42 || >=9.0.0.M1, <9.0.106`; fixed in `11.0.8`, `10.1.42`, `9.0.106`
- `org.apache.tomcat.embed:tomcat-embed-core` (Maven): affected `>=11.0.0-M1, <11.0.8 || >=10.1.0-M1, <10.1.42 || >=9.0.0.M1, <9.0.106`; fixed in `11.0.8`, `10.1.42`, `9.0.106`

## Machine-written summary

Summary written by Claude Haiku from the source advisory. Not reviewed by a person.

> Apache Tomcat (tomcat-catalina and tomcat-embed-core packages) versions 11.0.0-M1 through 11.0.7, 10.1.0-M1 through 10.1.41, and 9.0.0.M1 through 9.0.105 are affected by a session fixation flaw in the rewrite valve. The source gives few details on the exact attacker requirements or impact. Upgrade to 11.0.8, 10.1.42, or 9.0.106, which contain the fix.

Written 2 Nov 2026.

## Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

## Severity and exploitation

- 6.5 Medium, CVSS 3.1: `CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N`, from GitHub Advisory Database

- **CISA KEV:** Not listed.
- **EPSS:** 0.0095, the 61st percentile, on 13 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

## Timeline

- 31 Oct 2026, 14:20 UTC: First seen by agentprime
- 31 Oct 2026, 14:20 UTC: [Confirmed by OSV](https://osv.dev/vulnerability/GHSA-23hv-mwm6-g8jf)

## Sources

- [GitHub Advisory Database: GHSA-23hv-mwm6-g8jf](https://github.com/advisories/GHSA-23hv-mwm6-g8jf)
- [OSV: GHSA-23hv-mwm6-g8jf](https://osv.dev/vulnerability/GHSA-23hv-mwm6-g8jf)
- <https://nvd.nist.gov/vuln/detail/CVE-2025-55668>
- <https://github.com/apache/tomcat/commit/8621e4c6ba2c916a41eb34cb0f781171ead33fb6>
- <https://github.com/apache/tomcat/commit/90306d971bb8b8393336d893644124fb2ca11d21>
- <https://github.com/apache/tomcat/commit/9c3673ba04009377cb0c81ccb6cf5078aec1aa95>
- <https://github.com/apache/tomcat>
- <https://lists.apache.org/thread/v6bknr96rl7l1qxkl1c03v0qdvbbqs47>
- <https://tomcat.apache.org/security-10.html>
- <https://tomcat.apache.org/security-11.html>
- <https://tomcat.apache.org/security-9.html>
- <http://www.openwall.com/lists/oss-security/2025/08/13/3>

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.

## Check whether this affects you

A Match means an installed version is in the affected range above. Most don’t affect the app; agentprime hasn’t analysed this one yet.

- With the agentprime MCP server (<https://api.agentprime.io/mcp>), ask your agent to check the project: `check_lockfile` sends a lockfile, `check_packages` a list of installed packages, and both return the Matches and the upgrades that clear them. `get_advisory` returns this record. Setup: <https://agentprime.io/mcp.md>
- In a browser: <https://agentprime.io/check/> reads your lockfile in the browser, never uploading it.
- Whether it touches your code, with file and line: the Claude Code plugin, <https://agentprime.io/plugin.md>
- As JSON: <https://api.agentprime.io/v1/advisories/GHSA-23hv-mwm6-g8jf>, or `POST https://api.agentprime.io/v1/match` with your packages (<https://agentprime.io/api.md>)

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The web page: <https://agentprime.io/advisories/GHSA-23hv-mwm6-g8jf/>. Everything for agents: <https://agentprime.io/llms.txt>.