# Armeria SAML authentication bypass due to missing validation on unsigned SAML messages

Advisory record · `GHSA-4m6j-23p2-8c54`

- **Identifiers:** `GHSA-4m6j-23p2-8c54` · `CVE-2024-1735`
- **State:** Confirmed
- **Severity:** CVSS 9.1 Critical
- **Critical:** Yes: CVSS 9+
- **Weakness (CWE):** [CWE-287](https://cwe.mitre.org/data/definitions/287.html) · [CWE-304](https://cwe.mitre.org/data/definitions/304.html)
- **Tags:** [Authentication bypass](https://agentprime.io/advisories/tag/auth-bypass.md)
- **Published:** 26 Feb 2024
- **Updated:** 8 Jul 2026
- **Reviewed by a person:** No

Published by the GitHub Advisory Database at 26 Feb 2024, 20:04 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

## Critical

Critical, because:

- CVSS score 9.1: 9.0 or more.

How we decide what’s critical: <https://agentprime.io/advisories/critical.md>

## Affected packages

- `com.linecorp.armeria:armeria-saml` (Maven): affected `<1.27.2`; fixed in `1.27.2`

## Machine-written summary

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

> Armeria's armeria-saml package, versions before 1.27.2, accepts unsigned SAML messages such as assertions and logout requests instead of rejecting them by default. An attacker can forge such a message to authenticate as another user without valid credentials. Upgrade to armeria-saml 1.27.2 or later; the source lists no workaround.

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

- 9.1 Critical, CVSS 3.1: `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N`, from CNA (LY-Corporation)

- **CISA KEV:** Not listed.
- **EPSS:** 0.0083, the 58th percentile, on 14 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

## Timeline

- 31 Oct 2026, 14:19 UTC: First seen by agentprime
- 31 Oct 2026, 14:19 UTC: [Confirmed by OSV](https://osv.dev/vulnerability/GHSA-4m6j-23p2-8c54)

## Sources

- [GitHub Advisory Database: GHSA-4m6j-23p2-8c54](https://github.com/advisories/GHSA-4m6j-23p2-8c54)
- [OSV: GHSA-4m6j-23p2-8c54](https://osv.dev/vulnerability/GHSA-4m6j-23p2-8c54)
- <https://github.com/line/armeria/security/advisories/GHSA-4m6j-23p2-8c54>
- <https://nvd.nist.gov/vuln/detail/CVE-2024-1735>
- <https://github.com/line/armeria/commit/b2aa9f49b46a7b0e03d8b8d753809cd1e8e2016c>
- <https://github.com/line/armeria>
- <https://github.com/line/armeria/blob/0efc776988d71be4da6e506ec8a33c2b7b43f567/saml/src/main/java/com/linecorp/armeria/server/saml/SamlMessageUtil.java#L160-L163>
- <https://github.com/line/armeria/releases/tag/armeria-1.27.2>

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-4m6j-23p2-8c54>, 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-4m6j-23p2-8c54/>. Everything for agents: <https://agentprime.io/llms.txt>.