# Keycloak Vulnerable to Improper Validation of Specified Quantity in Input

Advisory record · `GHSA-f6r7-6w34-x2gp`

- **Identifiers:** `GHSA-f6r7-6w34-x2gp` · `CVE-2026-9801`
- **State:** Confirmed
- **Severity:** CVSS 4.9 Medium
- **Critical:** No
- **Weakness (CWE):** [CWE-1284](https://cwe.mitre.org/data/definitions/1284.html)
- **Tags:** [CWE-1284](https://agentprime.io/advisories/tag/cwe-1284.md)
- **Published:** 28 May 2026
- **Updated:** 1 Jul 2026
- **Reviewed by a person:** No

Published by the GitHub Advisory Database at 28 May 2026, 06:31 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

## Affected packages

- `org.keycloak:keycloak-ldap-federation` (Maven): affected `<26.6.3`; fixed in `26.6.3`

## Machine-written summary

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

> Keycloak's keycloak-ldap-federation package is affected in versions before 26.6.3. An attacker with high privileges, such as a realm administrator who configures a malicious LDAP server, or someone who has compromised an upstream LDAP server, can send a malformed LDAP password policy response during password authentication. This triggers an OutOfMemoryError that terminates the Keycloak JVM, causing a denial of service for all realms on the affected node. Upgrade to version 26.6.3.

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

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

- **CISA KEV:** Not listed.
- **EPSS:** 0.0048, the 41st percentile, on 7 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-f6r7-6w34-x2gp)

## Sources

- [GitHub Advisory Database: GHSA-f6r7-6w34-x2gp](https://github.com/advisories/GHSA-f6r7-6w34-x2gp)
- [OSV: GHSA-f6r7-6w34-x2gp](https://osv.dev/vulnerability/GHSA-f6r7-6w34-x2gp)
- <https://nvd.nist.gov/vuln/detail/CVE-2026-9801>
- <https://github.com/keycloak/keycloak/issues/49434>
- <https://github.com/keycloak/keycloak/pull/49514>
- <https://github.com/keycloak/keycloak/commit/2c4fe42235ba8c265b1da3a30541a270d5bd8c39>
- <https://access.redhat.com/errata/RHSA-2026:25097>
- <https://access.redhat.com/errata/RHSA-2026:25098>
- <https://access.redhat.com/errata/RHSA-2026:30049>
- <https://access.redhat.com/errata/RHSA-2026:30050>
- <https://access.redhat.com/security/cve/CVE-2026-9801>
- <https://bugzilla.redhat.com/show_bug.cgi?id=2482473>
- <https://github.com/keycloak/keycloak>

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-f6r7-6w34-x2gp>, 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-f6r7-6w34-x2gp/>. Everything for agents: <https://agentprime.io/llms.txt>.