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HIGH

CVE-2026-18212

CVSS v3

7.5

HIGH

EPSS Score

0.5 %

exploit probability, as of 2026-09-28

CISA KEV

No

known exploited

Exploitation

—

SSVC status

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.

Technical details

Published
2026-09-16
Last Modified
2026-09-16

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.

Is CVE-2026-18212 actively exploited?

Active exploitation of CVE-2026-18212 has not been confirmed. Its EPSS score was 0.5% on 2026-09-28, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2026-18212?

CVE-2026-18212 has a CVSS v3 base score of 7.5 (HIGH severity).

Is CVE-2026-18212 affecting your environment?

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