Vulnerability in Red Hat Build Of Keycloak
CVE-2026-18212
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.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.
EPSS exploit prediction
EPSS: 0.007 (53.3th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 53rd percentile — 53.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.005 · newest: 0.007 · change: +0.002
Affected products
Weakness classification (CWE)
References
- access.redhat.com/security/cve/CVE-2026-18212 (vdb-entry)
- bugzilla.redhat.com/show_bug.cgi (issue-tracking)
- access.redhat.com/errata/RHSA-2026:68276 (vendor-advisory)
- access.redhat.com/errata/RHSA-2026:68277 (vendor-advisory)
- access.redhat.com/errata/RHSA-2026:68278 (vendor-advisory)
- access.redhat.com/errata/RHSA-2026:68280 (vendor-advisory)
Frequently asked questions
- What is CVE-2026-18212?
- CVE-2026-18212 is a high-severity vulnerability in Red Hat Build Of Keycloak, classified under Missing Release of Memory after Effective Lifetime. CVSS score: 7.5/10. Published 2026-09-16.
- How severe is CVE-2026-18212?
- High severity. CVSS v3 base score is 7.5 out of 10.