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Description

A flaw was found in Keycloak. An unauthenticated remote attacker can trigger an application level Denial of Service (DoS) by sending a highly compressed SAMLRequest through the SAML Redirect Binding. The server fails to enforce size limits during DEFLATE decompression, leading to an OutOfMemoryError (OOM) and subsequent process termination. This vulnerability allows an attacker to disrupt the availability of the service.

PUBLISHED Reserved 2026-02-16 | Published 2026-03-18 | Updated 2026-03-18 | Assigner redhat




MEDIUM: 5.3CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

Problem types

Improper Handling of Highly Compressed Data (Data Amplification)

Product status

Default status
affected

26.4.10-1 (rpm) before *
unaffected

Default status
affected

26.4-12 (rpm) before *
unaffected

Default status
affected

26.4-12 (rpm) before *
unaffected

Default status
unaffected

Timeline

2026-02-16:Reported to Red Hat.
2026-02-16:Made public.

Credits

Red Hat would like to thank Sho Odagiri (GMO Cybersecurity by Ierae, Inc.) for reporting this issue.

References

access.redhat.com/errata/RHSA-2026:3947 (RHSA-2026:3947) vendor-advisory

access.redhat.com/errata/RHSA-2026:3948 (RHSA-2026:3948) vendor-advisory

access.redhat.com/security/cve/CVE-2026-2575 vdb-entry

bugzilla.redhat.com/show_bug.cgi?id=2440149 (RHBZ#2440149) issue-tracking

cve.org (CVE-2026-2575)

nvd.nist.gov (CVE-2026-2575)

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