Medium severity · published Oct 29, 2026
CVE-2026-117859
Keycloak-services: keycloak-services: par single-use bypass via flow restart
New
5.4
CVSS
–
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
None
Confidentiality
Low
Integrity
Low
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
RH
Red Hat Build of Keycloak · Red Hat
All versions, or not specified · source: vendor
Affected product
RH
Red Hat Build of Keycloak
Red Hat
More from Red Hat Build of Keycloak
9.8
CVE-2026-42581
Netty: HTTP/1.0 TE+CL Coexistence Bypasses Smuggling Sanitization
9.8
CVE-2026-33228
flatted: Prototype Pollution via parse()
9.1
CVE-2026-42584
Netty: HttpClientCodec response desynchronization
9.1
CVE-2026-42579
Netty: DNS Codec Input Validation Bypass in Netty (Encoder + Decoder)
8.2
CVE-2026-93569
Io.netty/netty-codec-http2: http/1 absolute-form host mismatch is translated to http/2 :authority, overriding the request-target authority