Red HatCVE-2026-18212
SAML Redirect Binding implementation of Keycloak: denial of service
High7.5CVE-2026-18212 · Published Sep 16, 2026
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 versions
| Package | Affected | Fixed in |
|---|---|---|
| Red Hat Data Grid 8 Product | all versions | No fix yet |
| Red Hat build of Keycloak 26.4.16 Product | all versions | No fix yet |
| all versions | No fix yet | |
| Red Hat build of Keycloak 26.6.7 Product | all versions | No fix yet |
| all versions | No fix yet | |
| all versions | No fix yet |
Details and references
- CVSS 3.1
- CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- Severity from
- the vendor (its own CVE record or advisory)
- Weakness
- CWE-401
- www.cve.org/CVERecord?id=CVE-2026-18212
- nvd.nist.gov/vuln/detail/CVE-2026-18212
- access.redhat.com/errata/RHSA-2026:68276
- access.redhat.com/errata/RHSA-2026:68277
- access.redhat.com/errata/RHSA-2026:68278
- access.redhat.com/errata/RHSA-2026:68280
- access.redhat.com/security/cve/CVE-2026-18212
- bugzilla.redhat.com/show_bug.cgi?id=2508307
More Red Hat advisories
All Red Hat| Date | Advisory | Severity | Fixed in |
|---|---|---|---|
| Sep 16 | Red Hat Quay 3: attacker could inject arbitrary code | High8.0 | No fix yet |
| Sep 16 | Red Hat sequoia-openpgp. The: improper signature check | High7.4 | No fix yet |
| Sep 16 | Red Hat flightctl: race condition | Medium6.6 | No fix yet |
| Sep 16 | Red Hat first-broker-login flow: improper authentication | Medium5.3 | No fix yet |
| Sep 16 | Red Hat Data Grid 8: missing authorization | High7.2 | No fix yet |
| Sep 16 | Red Hat build of Keycloak: resource exhaustion | High7.5 | No fix yet |