# Keycloak: Denial of Service due to excessive SAMLRequest decompression

Advisory record · `GHSA-xv6h-r36f-3gp5`

- **Identifiers:** `GHSA-xv6h-r36f-3gp5` · `BIT-keycloak-2026-2575` · `CVE-2026-2575`
- **State:** Confirmed
- **Severity:** CVSS 5.3 Medium
- **Critical:** No
- **Weakness (CWE):** [CWE-409](https://cwe.mitre.org/data/definitions/409.html)
- **Tags:** [CWE-409](https://agentprime.io/advisories/tag/cwe-409.md)
- **Published:** 18 Mar 2026
- **Updated:** 6 Oct 2026
- **Reviewed by a person:** No

Published by the GitHub Advisory Database at 18 Mar 2026, 06:31 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

## Affected packages

- `org.keycloak:keycloak-saml-adapter-core` (Maven): affected `<26.5.4`; fixed in `26.5.4`
- `org.keycloak:keycloak-saml-core` (Maven): affected `<26.5.4`; fixed in `26.5.4`
- `org.keycloak:keycloak-services` (Maven): affected `<26.5.4`; fixed in `26.5.4`

## Machine-written summary

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

> Keycloak's keycloak-saml-adapter-core, keycloak-saml-core and keycloak-services packages before 26.5.4 are vulnerable. An unauthenticated remote attacker can send a highly compressed SAMLRequest through the SAML Redirect Binding, which the server fails to size-limit during decompression, causing an out-of-memory error and process termination. Upgrade to version 26.5.4 or later.

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

- 5.3 Medium, CVSS 3.1: `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L`, from CNA (redhat)

- **CISA KEV:** Not listed.
- **EPSS:** 0.0066, the 51st percentile, on 6 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

## Timeline

- 31 Oct 2026, 14:16 UTC: First seen by agentprime
- 31 Oct 2026, 14:16 UTC: [Confirmed by OSV](https://osv.dev/vulnerability/GHSA-xv6h-r36f-3gp5)

## Sources

- [GitHub Advisory Database: GHSA-xv6h-r36f-3gp5](https://github.com/advisories/GHSA-xv6h-r36f-3gp5)
- [OSV: GHSA-xv6h-r36f-3gp5](https://osv.dev/vulnerability/GHSA-xv6h-r36f-3gp5)
- <https://nvd.nist.gov/vuln/detail/CVE-2026-2575>
- <https://github.com/keycloak/keycloak/issues/46372>
- <https://github.com/keycloak/keycloak/commit/4f90ef67f698dfb45df0d2f4981271a7c8b47f04>
- <https://access.redhat.com/errata/RHSA-2026:3947>
- <https://access.redhat.com/errata/RHSA-2026:3948>
- <https://access.redhat.com/errata/RHSA-2026:76128>
- <https://access.redhat.com/errata/RHSA-2026:76129>
- <https://access.redhat.com/errata/RHSA-2026:76130>
- <https://access.redhat.com/errata/RHSA-2026:76132>
- <https://access.redhat.com/errata/RHSA-2026:76134>
- <https://access.redhat.com/security/cve/CVE-2026-2575>
- <https://bugzilla.redhat.com/show_bug.cgi?id=2440149>

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-xv6h-r36f-3gp5>, or `POST https://api.agentprime.io/v1/match` with your packages (<https://agentprime.io/api.md>)

---

The web page: <https://agentprime.io/advisories/GHSA-xv6h-r36f-3gp5/>. Everything for agents: <https://agentprime.io/llms.txt>.