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Description

A flaw was found in Keycloak. An authenticated attacker can perform Server-Side Request Forgery (SSRF) by manipulating the `client_session_host` parameter during refresh token requests. This occurs when a Keycloak client is configured to use the `backchannel.logout.url` with the `application.session.host` placeholder. Successful exploitation allows the attacker to make HTTP requests from the Keycloak server’s network context, potentially probing internal networks or internal APIs, leading to information disclosure.

PUBLISHED Reserved 2026-03-26 | Published 2026-03-26 | Updated 2026-04-01 | Assigner redhat




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

Problem types

Server-Side Request Forgery (SSRF)

Product status

Default status
affected

Default status
affected

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affected

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affected

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affected

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affected

Timeline

2026-03-26:Reported to Red Hat.
2026-03-26:Made public.

Credits

Red Hat would like to thank Evan Hendra (Independent Security Researcher) for reporting this issue.

References

access.redhat.com/security/cve/CVE-2026-4874 vdb-entry

bugzilla.redhat.com/show_bug.cgi?id=2451611 (RHBZ#2451611) issue-tracking

cve.org (CVE-2026-4874)

nvd.nist.gov (CVE-2026-4874)

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