# CVE-2026-118030: Keycloak-services: keycloak-services: hotp race condition allows single otp code reuse across concurrent logins

Status: published. Published: 2026-10-29. Updated: 2026-11-06.

A flaw was found in the HOTP authentication mechanism of the keycloak-services component, which provides identity and access management services. The issue occurs because the system validates a one-time password and updates its internal counter in two separate steps without proper locking. An attacker with a users password could exploit this timing gap to use a single one-time code to log in multiple times simultaneously.

## Remediation

- workaround: Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability. (source: CNA: redhat)

## Affected products and versions

- Red Hat / Red Hat Build of Keycloak (keycloak-services): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat Build of Keycloak (rhbk/keycloak-rhel9): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat Single Sign-On 7 (keycloak-services): Version range not reported. Source: CNA: redhat

## Severity and prioritization

- CVSS 3.1: 4.2 (medium); CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:N; source: CNA: redhat

- CISA KEV: No listing in collected sources

- EPSS: 0.16% as of 2026-11-05; percentile 5.53%

- SSVC: exploitation none; automatable no; technical impact partial; source ADP: CISA-ADP

- Weaknesses: CWE-362

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://access.redhat.com/security/cve/CVE-2026-118030 (CNA: redhat; vdb-entry, x_refsource_REDHAT)

- https://bugzilla.redhat.com/show_bug.cgi?id=2562005 (CNA: redhat; issue-tracking, x_refsource_REDHAT)

## Provenance

- CNA: redhat: https://www.cve.org/CVERecord?id=CVE-2026-118030; retrieved 2026-11-06; source updated 2026-11-06

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2026-118030; retrieved 2026-11-06; source updated Not reported

Revision: 5fe2f862f327677bf06fbbf3f0a59fe41ce7a317c0f9883893b0d9c70aba1853

Canonical: https://y2.dev/cve/CVE-2026-118030

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