VulnerabilityPublished 29 Oct 2026

CVE-2026-118030: Red Hat Build of Keycloak · Race Condition

Affects Red Hat Build of KeycloakSource CVE Database V5

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Not known to be exploited · CVSS 4.2 Medium.

Data as of 29 Oct 2026, 07:26 UTC

CVSS 3.1 base score

4.2Medium

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	4.2

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

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

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: Low: The attacker is authorized with (i.e., requires) privileges that provide basic user capabilities that could normally affect only settings and files owned by a user. Alternatively, an attacker with Low privileges may have the ability to cause an impact only to non-sensitive resources.
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: Low: There is some loss of confidentiality. Access to some restricted information is obtained, but the attacker does not have control over what information is obtained, or the amount or kind of loss is limited. The information disclosure does not cause a direct, serious loss to the impacted component.
Integrity: Low: Modification of data is possible, but the attacker does not have control over the consequence of a modification, or the amount of modification is limited. The data modification does not have a direct, serious impact on the impacted component.
Availability: None: There is no impact to availability within the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 29 Oct 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 29 Oct 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.

What to do

Affected software

Product	Affected	Fixed in
Red Hat Build of Keycloakkeycloak-services	Affected–	Fixed in–
Red Hat Build of Keycloakrhbk/keycloak-rhel9	Affected–	Fixed in–
Red Hat Single Sign-On 7keycloak-services	Affected–	Fixed in–

AI-suggested

Red Hat currently states that no mitigation is available or that existing options do not meet their criteria for ease of use, deployment, applicability, or stability. Users should monitor Red Hat advisories for future updates or fixes. Since exploitation requires valid credentials and a race condition, enforcing strong password policies and limiting credential exposure may reduce risk but do not directly mitigate the vulnerability.

Description

CVE-2026-118030 is a race condition vulnerability in the HOTP authentication mechanism of the keycloak-services component used by Red Hat Build of Keycloak. The flaw arises because the system validates a one-time password and updates its internal counter in two separate steps without proper synchronization. An attacker who already has a user's password could exploit this timing gap to reuse a single one-time password to log in multiple times concurrently. The vulnerability is rated as medium severity with a CVSS score of 4.2. Currently, no effective mitigation or patch meeting Red Hat's criteria is available.

Impact

Successful exploitation allows an attacker with valid user credentials to reuse a single one-time password multiple times concurrently, potentially bypassing the intended one-time use restriction of HOTP codes. This could lead to unauthorized concurrent sessions under the same user identity. The confidentiality and integrity impacts are low, and availability is unaffected.

Summary

This vulnerability in Red Hat Build of Keycloak's HOTP authentication mechanism involves improper synchronization between the validation of a one-time password and the increment of the internal counter. Because these operations are not atomic, an attacker possessing valid user credentials can exploit the race condition to reuse a single one-time password for multiple simultaneous logins. The issue is classified as a race condition (CWE-362). Red Hat has assessed the severity as moderate due to the requirement of valid credentials and the complexity of winning the race condition.

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 29 Oct 2026, 07:06 UTC

Technical details

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