CVE-2026-3872 | Keycloak: keycloak: information disclosure due to redirect_uri validation bypass

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.

Published: 2026-04-02 Last update: 2026-04-16 Assigner: [email protected] Source: [email protected]
NVD Status：Analyzed，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2026-3872 is rated Low Risk (32.5/100): CVSS High severity, with low exploitation likelihood (EPSS 0.03%). Monitor for updates and reassess as exploit intelligence or EPSS changes.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2026-3872

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-04-03 — 0.03% —

Full EPSS history (1 record total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-3872

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.3 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:N)
Service keeps running; no real outage angle.
 2.1 5.2 [email protected]

Weakness enumeration for CVE-2026-3872

GitHub Security Advisory for CVE-2026-3872

GHSA-cjm2-j6cm-6p6m · Severity: high · Ecosystem: maven — Keycloak: Redirect URI validation bypass via ..;/ path traversal in OIDC auth endpoint

OS Trackers for CVE-2026-3872

vendor priority summary link
redhat high — https://access.redhat.com/security/cve/CVE-2026-3872

Affected software / configurations for CVE-2026-3872

Vendor Product Version Raw CPE
redhat build_of_keycloak — cpe:2.3:a:redhat:build_of_keycloak:-:*:*:*:text-only:*:*:*
redhat build_of_keycloak 26.2 cpe:2.3:a:redhat:build_of_keycloak:26.2:*:*:*:text-only:*:*:*
redhat build_of_keycloak 26.2.15 cpe:2.3:a:redhat:build_of_keycloak:26.2.15:*:*:*:text-only:*:*:*
redhat build_of_keycloak 26.4 cpe:2.3:a:redhat:build_of_keycloak:26.4:*:*:*:text-only:*:*:*
redhat build_of_keycloak 26.4.11 cpe:2.3:a:redhat:build_of_keycloak:26.4.11:*:*:*:text-only:*:*:*

References for CVE-2026-3872

cvelogic Threat Intelligence