CVE-2026-18212 (CVSS 7.5)

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.

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CVSS v3.1 Score

7.5

HIGH

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Weakness Type (CWE)

CWE-401 CWE-401

References

Other 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

Frequently Asked Questions

What is 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. It has a CVSS v3.1 base score of 7.5 (HIGH).

How severe is CVE-2026-18212? +

CVE-2026-18212 has a CVSS v3.1 score of 7.5 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching.

How do I check if I'm vulnerable to CVE-2026-18212? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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