Raw vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:NSummary
CVE-2026-3872 is a high-severity Open Redirect (CWE-601) vulnerability in Redhat Build Of Keycloak. Its CVSS base score is 7.3 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Phishing (T1566); ranked at the 36th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified map to SI-10 (Information Input Validation) and AC-4 (Information Flow Enforcement) — see the control section below for these in your framework.
Deeper analysis AI-assisted summary
Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.
CVE-2026-3872 is a vulnerability in Keycloak that enables an attacker who controls another path on the same web server to bypass restrictions on allowed paths in redirect Uniform Resource Identifiers (URIs) that employ wildcards. This flaw, classified under CWE-601 (URL Redirector Abuse), can result in the theft of an access token and information disclosure. The issue carries a CVSS v3.1 base score of 7.3 (AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:N).
Exploitation requires an attacker with low privileges and control over another path on the same web server hosting Keycloak, along with network access and user interaction. A successful attack allows the bypass of wildcard-based redirect URI validations, enabling the theft of access tokens and achieving high impacts on confidentiality and integrity, such as unauthorized access to protected resources.
Red Hat has issued multiple errata to address this vulnerability, including RHSA-2026:6475, RHSA-2026:6476, RHSA-2026:6477, and RHSA-2026:6478. Further details on the CVE, including mitigation guidance, are available at https://access.redhat.com/security/cve/CVE-2026-3872.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-18206
Vulnerability Data
A flaw was found in Keycloak. This issue allows an attacker, who controls another path on the same web server, to bypass the allowed path in redirect Uniform Resource Identifiers (URIs) that use a wildcard. A successful attack may lead…
more
to the theft of an access token, resulting in information disclosure.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
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V3.7.2
Mitigating Controls (NIST 800-53 r5) AI
Input validation directly checks and rejects untrusted redirect targets before they are used in a response.
Information flow enforcement can restrict redirects to only approved/trusted destinations, stopping untrusted user-supplied URLs from being followed.
Mitigating Controls (NIST CSF 2.0) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.
Secure SDLC practices directly require input validation and untrusted-redirect controls that prevent CWE-601.
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.
Preventing access to attacker-controlled or malicious sites stops users from being redirected to untrusted locations via open-redirect or phishing links.