CVE-2026-18212

Summary

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.

Affected Software

VendorProductVersion RangeStatus
Red HatRed Hat build of Keycloak 26.426.4.16-2 < *unaffected
Red HatRed Hat build of Keycloak 26.426.4-26 < *unaffected
Red HatRed Hat build of Keycloak 26.426.4-26 < *unaffected
Red HatRed Hat build of Keycloak 26.626.6.7-3 < *unaffected
Red HatRed Hat build of Keycloak 26.626.6-20 < *unaffected
Red HatRed Hat build of Keycloak 26.626.6-20 < *unaffected

Weaknesses

  • CWE-401: Missing Release of Memory after Effective Lifetime

Workarounds

Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.

ADP Enrichment

CISA ADP Vulnrichment

  • SSVC:
  • Exploitation: none
    • Automatable: yes
    • Technical Impact: partial

References