CVE-2026-18212
Keycloak-services: keycloak-services: saml redirect deflate helpers leak native zlib state
- State
- Published
- Severity
- 7.5 High
- Published
- Sep 16, 2026
- Updated
- Sep 16, 2026
- Reserved
- Jul 29, 2026
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.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 3.1 | 7.5 High | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H | redhat |
Weaknesses
- CWE-401 Missing Release of Memory after Effective Lifetime
Affected Products
| Product | Versions |
|---|---|
Red Hat build of Keycloak 26.4Red Hat |
|
Red Hat build of Keycloak 26.4Red Hat |
|
Red Hat build of Keycloak 26.4Red Hat |
|
Red Hat build of Keycloak 26.4.16Red Hat | |
Red Hat build of Keycloak 26.4.16Red Hat | |
Red Hat build of Keycloak 26.6Red Hat |
|
Red Hat build of Keycloak 26.6Red Hat |
|
Red Hat build of Keycloak 26.6Red Hat |
|
Red Hat build of Keycloak 26.6.7Red Hat | |
Red Hat build of Keycloak 26.6.7Red Hat | |
Red Hat build of Keycloak 26.6.7Red Hat | |
Red Hat Data Grid 8Red Hat | |
Red Hat JBoss Enterprise Application Platform Expansion PackRed Hat | |
Red Hat Single Sign-On 7Red Hat |
References
- RHSA-2026:68276vendor-advisory
- RHSA-2026:68277vendor-advisory
- RHSA-2026:68278vendor-advisory
- RHSA-2026:68280vendor-advisory
- https://access.redhat.com/security/cve/CVE-2026-18212vdb-entry
- RHBZ#2508307issue-tracking
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