CVE-2026-3872: URL Redirection to Untrusted Site ('Open Redirect') in Red Hat Red Hat build of Keycloak 26.2
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 to the theft of an access token, resulting in information disclosure.
AI Analysis
Technical Summary
A vulnerability identified as CVE-2026-3872 affects Red Hat build of Keycloak 26.2, where an attacker who controls another path on the same web server can bypass allowed path restrictions in redirect URIs that use wildcards. This open redirect vulnerability (CWE-601) enables theft of access tokens, potentially causing information disclosure. The issue is present in versions before 26.2.15. Red Hat has published advisories and released version 26.2.15 that includes a fix for this vulnerability.
Potential Impact
Successful exploitation of this vulnerability can lead to theft of access tokens, resulting in unauthorized disclosure of sensitive information. The CVSS v3.1 score is 7.3 (High), reflecting network attack vector, low attack complexity, requiring low privileges and user interaction, with high confidentiality and integrity impact but no availability impact.
Mitigation Recommendations
Red Hat has released version 26.2.15 of the Red Hat build of Keycloak which includes a fix for CVE-2026-3872. Users should upgrade to version 26.2.15 or later to remediate this vulnerability. Before applying the update, it is recommended to back up existing installations, including applications, configuration files, and databases. No other mitigations are specified in the vendor advisories.
CVE-2026-3872: URL Redirection to Untrusted Site ('Open Redirect') in Red Hat Red Hat build of Keycloak 26.2
Description
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 to the theft of an access token, resulting in information disclosure.
CVSS v3.1
Score 7.3high
Affected software
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
A vulnerability identified as CVE-2026-3872 affects Red Hat build of Keycloak 26.2, where an attacker who controls another path on the same web server can bypass allowed path restrictions in redirect URIs that use wildcards. This open redirect vulnerability (CWE-601) enables theft of access tokens, potentially causing information disclosure. The issue is present in versions before 26.2.15. Red Hat has published advisories and released version 26.2.15 that includes a fix for this vulnerability.
Potential Impact
Successful exploitation of this vulnerability can lead to theft of access tokens, resulting in unauthorized disclosure of sensitive information. The CVSS v3.1 score is 7.3 (High), reflecting network attack vector, low attack complexity, requiring low privileges and user interaction, with high confidentiality and integrity impact but no availability impact.
Mitigation Recommendations
Red Hat has released version 26.2.15 of the Red Hat build of Keycloak which includes a fix for CVE-2026-3872. Users should upgrade to version 26.2.15 or later to remediate this vulnerability. Before applying the update, it is recommended to back up existing installations, including applications, configuration files, and databases. No other mitigations are specified in the vendor advisories.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- redhat
- Date Reserved
- 2026-03-10T09:25:23.875Z
- Cvss Version
- 3.1
- State
- PUBLISHED
- Vendor Advisory Urls
- [{"url":"https://access.redhat.com/errata/RHSA-2026:6475","vendor":"Red Hat"},{"url":"https://access.redhat.com/errata/RHSA-2026:6476","vendor":"Red Hat"},{"url":"https://access.redhat.com/errata/RHSA-2026:6477","vendor":"Red Hat"},{"url":"https://access.redhat.com/errata/RHSA-2026:6478","vendor":"Red Hat"},{"url":"https://access.redhat.com/security/cve/CVE-2026-3872","vendor":"Red Hat"}]
Threat ID: 69ce6a44e6bfc5ba1dd993a3
Added to database: 04/02/2026, 13:08:20 UTC
Last enriched: 07/15/2026, 09:09:26 UTC
Last updated: 07/31/2026, 19:22:58 UTC
Views: 1023
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