# Keycloak: Privilege escalation via forged authorization codes due to SingleUseObjectProvider isolation flaw

Advisory record · `GHSA-hj93-h7pg-fh6v`

- **Identifiers:** `GHSA-hj93-h7pg-fh6v` · `BIT-keycloak-2026-4282` · `CVE-2026-4282`
- **State:** Confirmed
- **Severity:** CVSS 7.4 High
- **Critical:** No
- **Weakness (CWE):** [CWE-653](https://cwe.mitre.org/data/definitions/653.html)
- **Tags:** [CWE-653](https://agentprime.io/advisories/tag/cwe-653.md)
- **Published:** 2 Apr 2026
- **Updated:** 10 Sept 2026
- **Reviewed by a person:** No

Published by the GitHub Advisory Database at 2 Apr 2026, 15:31 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

## Affected packages

- `org.keycloak:keycloak-services` (Maven): affected `<26.5.7`; fixed in `26.5.7`

## Machine-written summary

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

> Keycloak's keycloak-services package (Maven org.keycloak:keycloak-services) is affected in versions before 26.5.7. Because the SingleUseObjectProvider store lacks proper type and namespace isolation, an unauthenticated attacker can forge authorization codes and obtain admin-capable access tokens, leading to privilege escalation. Upgrade to version 26.5.7 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

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

- **CISA KEV:** Not listed.
- **EPSS:** 0.0043, the 37th percentile, on 5 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

## Timeline

- 31 Oct 2026, 14:17 UTC: First seen by agentprime
- 31 Oct 2026, 14:17 UTC: [Confirmed by OSV](https://osv.dev/vulnerability/GHSA-hj93-h7pg-fh6v)

## Sources

- [GitHub Advisory Database: GHSA-hj93-h7pg-fh6v](https://github.com/advisories/GHSA-hj93-h7pg-fh6v)
- [OSV: GHSA-hj93-h7pg-fh6v](https://osv.dev/vulnerability/GHSA-hj93-h7pg-fh6v)
- <https://nvd.nist.gov/vuln/detail/CVE-2026-4282>
- <https://github.com/keycloak/keycloak/issues/47719>
- <https://github.com/keycloak/keycloak/commit/9046f201125a6fd6be9c116b99d348509d99d4a5>
- <https://access.redhat.com/errata/RHSA-2026:6475>
- <https://access.redhat.com/errata/RHSA-2026:6476>
- <https://access.redhat.com/errata/RHSA-2026:6477>
- <https://access.redhat.com/errata/RHSA-2026:6478>
- <https://access.redhat.com/security/cve/CVE-2026-4282>
- <https://bugzilla.redhat.com/show_bug.cgi?id=2448061>
- <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-hj93-h7pg-fh6v>, or `POST https://api.agentprime.io/v1/match` with your packages (<https://agentprime.io/api.md>)

---

The web page: <https://agentprime.io/advisories/GHSA-hj93-h7pg-fh6v/>. Everything for agents: <https://agentprime.io/llms.txt>.