CVE-2026-18212
High
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.
SeverityHigh
CVSS7.5
Exploit probability—
Product
Build Keycloak 26.4
PublishedSep 16, 2026
First seenSep 16, 2026
Weakness typeCWE-401CWE-401
How to fix
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| build_keycloak 26.4 | No range specified | — |
| build_keycloak 26.6 | No range specified | — |
| Red Hat Red Hat Data Grid 8 | No range specified | — |
| Red Hat Red Hat Single Sign-On 7 | No range specified | — |
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