Vulnerability · Published Oct 29, 2026 · Assigned by redhat

CVE-2026-117859Keycloak-services: keycloak-services: par single-use bypass via flow restart

Medium 5.4

In plain English

A medium-severity security flaw in Red Hat Build of Keycloak from Red Hat. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 9% of all known vulnerabilities).

Severity (CVSS 3.1)5.4Medium

Exploit odds (30 days)0.2%top 91.0% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official description

A flaw was found in the Pushed Authorization Request PAR implementation of the keycloak-services component. The issue occurs when an authentication flow is restarted, which incorrectly clears the internal markers used to track PAR consumption while leaving the request active. This allows an attacker to reuse the same authorization request to obtain multiple access tokens, bypassing security requirements for single-use requests.

Affected products (as reported)

Vendor	Product	Versions
Red Hat	Red Hat Build of Keycloak	see references
Red Hat	Red Hat Build of Keycloak	see references
Red Hat	Red Hat Single Sign-On 7	see references

Weakness: CWE-670 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N

References

https://access.redhat.com/security/cve/CVE-2026-117859 vdb-entry, x_refsource_REDHAT
RHBZ#2561991 issue-tracking, x_refsource_REDHAT