CVE-2026-18569VulnerabilityPublished 3 Aug 2026Updated 8 Nov 2026

Bundesamt für Sicherheit in der Informationstechnik Open Source · RedHat Build of Keycloak: Schwachstelle ermöglicht Denial of Service

Affects Bundesamt für Sicherheit in der Informationstechnik Open SourceSource GCVE Database

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Authoritative record:CVE-2026-18569· Low 3.7

Not known to be exploited · CVSS 3.7 Low.

Data as of 9 Nov 2026, 13:49 UTC

CVSS 3.1 base score

3.7Low

How severe the flaw is on the 0–10 CVSS scale.

Thin evidence

One scorer or none

CVSS scores by source
CNA (redhat)	CVSS 3.1	3.7

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

Attack Vector: Network
Attack Complexity: High
Privileges Required: None
User Interaction: None
Scope: Unchanged
Confidentiality: None
Integrity: None
Availability: Low

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: High: A successful attack depends on conditions beyond the attacker's control. That is, a successful attack cannot be accomplished at will, but requires the attacker to invest in some measurable amount of effort in preparation or execution against the vulnerable component before a successful attack can be expected. For example, a successful attack may require an attacker to: gather knowledge about the environment in which the vulnerable target/component exists; prepare the target environment to improve exploit reliability; or inject themselves into the logical network path between the target and the resource requested by the victim in order to read and/or modify network communications (e.g., a man in the middle attack).
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: None: There is no loss of confidentiality within the impacted component.
Integrity: None: There is no loss of integrity within the impacted component.
Availability: Low: Performance is reduced or there are interruptions in resource availability. Even if repeated exploitation of the vulnerability is possible, the attacker does not have the ability to completely deny service to legitimate users. The resources in the impacted component are either partially available all of the time, or fully available only some of the time, but overall there is no direct, serious consequence to the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 4 Aug 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 9 Nov 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

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What to do

Affected software

Product	Affected	Fixed in
Red Hat build of Keycloak 26.6rhbk/keycloak-operator-bundle	Affected–	Fixed in–
Red Hat build of Keycloak 26.6rhbk/keycloak-rhel9	Affected–	Fixed in–
Red Hat build of Keycloak 26.6rhbk/keycloak-rhel9-operator	Affected–	Fixed in–
Red Hat build of Keycloak 26.6.8keycloak-services	Affected–	Fixed in–
Red Hat build of Keycloak 26.6.8rhbk-keycloak-rhel9/rhbk-keycloak-rhel9	Affected–	Fixed in–
Red Hat build of Keycloak 26.6.8rhbk-openshift-rhel9/rhbk-openshift-rhel9	Affected–	Fixed in–

AI-suggested

No effective mitigation or patch currently meets Red Hat's criteria for ease of use, applicability, or stability. Users should avoid configuring OIDC identity providers to skip signature validation to prevent exposure to this vulnerability.

Description

A vulnerability in the Red Hat Build of Keycloak affects the backchannel logout endpoint when configured with an OIDC identity provider that skips signature validation. This flaw allows an attacker with knowledge of specific session identifiers to force targeted users to be logged out, causing a limited denial of service. The issue arises from the failure to enforce signature validation on logout tokens under this non-default insecure configuration. The severity is assessed as low due to the requirement for a non-default setup and specific session knowledge.

Impact

Successful exploitation allows an attacker to force logout targeted brokered users, resulting in a limited denial of service for those individuals. There is no impact on confidentiality or integrity, and no privilege escalation or code execution is possible. The attack complexity is high, and no user interaction or privileges are required.

Summary

The vulnerability (CVE-2026-18569) exists in the keycloak-services component of the Red Hat Build of Keycloak, specifically in the backchannel logout endpoint. When an OpenID Connect (OIDC) identity provider is configured to skip signature validation, the system incorrectly accepts unsigned logout requests. An attacker who knows certain session details can exploit this to forcibly log out users, disrupting their sessions. The root cause is improper verification of cryptographic signatures (CWE-347) when signature validation is disabled. Red Hat rates the severity as low because exploitation requires a non-default insecure configuration and session knowledge.

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 9 Nov 2026, 13:49 UTC

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