# Apache Tomcat Improper Input Validation vulnerability

Advisory record · `GHSA-r6j3-px5g-cq3x`

- **Identifiers:** `GHSA-r6j3-px5g-cq3x` · `BIT-tomcat-2023-45648` · `CVE-2023-45648`
- **State:** Confirmed
- **Severity:** CVSS 5.3 Medium
- **Critical:** No
- **Weakness (CWE):** [CWE-20](https://cwe.mitre.org/data/definitions/20.html)
- **Tags:** [CWE-20](https://agentprime.io/advisories/tag/cwe-20.md)
- **Published:** 10 Oct 2023
- **Updated:** 12 Jun 2026
- **Reviewed by a person:** No

Published by the GitHub Advisory Database at 10 Oct 2023, 21:31 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

## Affected packages

- `org.apache.tomcat:tomcat` (Maven): affected `>=11.0.0-M1, <11.0.0-M12 || >=10.1.0-M1, <10.1.14 || >=9.0.0-M1, <9.0.81 || >=8.5.0, <8.5.94`; fixed in `11.0.0-M12`, `10.1.14`, `9.0.81`, `8.5.94`
- `org.apache.tomcat.embed:tomcat-embed-core` (Maven): affected `>=11.0.0-M1, <11.0.0-M12 || >=10.1.0-M1, <10.1.14 || >=9.0.0-M1, <9.0.81 || >=8.5.0, <8.5.94`; fixed in `11.0.0-M12`, `10.1.14`, `9.0.81`, `8.5.94`
- `org.apache.tomcat:tomcat-coyote` (Maven): affected `>=11.0.0-M1, <11.0.0-M12 || >=10.1.0-M1, <10.1.14 || >=9.0.0-M1, <9.0.81 || >=8.5.0, <8.5.94`; fixed in `11.0.0-M12`, `10.1.14`, `9.0.81`, `8.5.94`

## Machine-written summary

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

> Apache Tomcat versions 11.0.0-M1 through 11.0.0-M11, 10.1.0-M1 through 10.1.13, 9.0.0-M1 through 9.0.81, and 8.5.0 through 8.5.93 do not parse HTTP trailer headers correctly. An attacker can send a specially crafted invalid trailer header so that one request is treated as several, enabling request smuggling when Tomcat sits behind a reverse proxy. Upgrade to 11.0.0-M12, 10.1.14, 9.0.81, or 8.5.94 or later, which fix the issue.

Written 3 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

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

- **CISA KEV:** Not listed.
- **EPSS:** 0.059, the 93rd percentile, on 14 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-r6j3-px5g-cq3x)

## Sources

- [GitHub Advisory Database: GHSA-r6j3-px5g-cq3x](https://github.com/advisories/GHSA-r6j3-px5g-cq3x)
- [OSV: GHSA-r6j3-px5g-cq3x](https://osv.dev/vulnerability/GHSA-r6j3-px5g-cq3x)
- <https://nvd.nist.gov/vuln/detail/CVE-2023-45648>
- <https://github.com/apache/tomcat/commit/59583245639d8c42ae0009f4a4a70464d3ea70a0>
- <https://github.com/apache/tomcat/commit/8ecff306507be8e4fd3adee1ae5de1ea6661a8f4>
- <https://github.com/apache/tomcat/commit/c83fe47725f7ae9ae213568d9039171124fb7ec6>
- <https://github.com/apache/tomcat/commit/eb5c094e5560764cda436362254997511a3ca1f6>
- <https://github.com/apache/tomcat>
- <https://lists.apache.org/thread/2pv8yz1pyp088tsxfb7ogltk9msk0jdp>
- <https://lists.debian.org/debian-lts-announce/2023/10/msg00020.html>
- <https://security.netapp.com/advisory/ntap-20231103-0007>
- <https://www.debian.org/security/2023/dsa-5521>
- <https://www.debian.org/security/2023/dsa-5522>
- <http://www.openwall.com/lists/oss-security/2023/10/10/10>

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-r6j3-px5g-cq3x>, or `POST https://api.agentprime.io/v1/match` with your packages (<https://agentprime.io/api.md>)

---

The web page: <https://agentprime.io/advisories/GHSA-r6j3-px5g-cq3x/>. Everything for agents: <https://agentprime.io/llms.txt>.