Auth bypass in Quarkus

CVE-2026-39852

Quarkus is a Java framework for building cloud-native applications. In versions prior to 3.20.6.1, 3.27.3.1, 3.33.1.1, 3.35.1.1, 3.34.7, and 3.35.2, a path normalization inconsistency between the security layer and the routing layer allows unauthenticated or lower-privileged users to bypass HTTP path-based authorization policies. Quarkus's security layer performs authorization checks on the raw URL path which preserves matrix parameters (semicolons), while RESTEasy Reactive's routing layer strips matrix parameters before matching endpoints. An attacker can append a semicolon and arbitrary text to a request URL (e.g., /api/admin;anything) to bypass policies protecting /api/admin while still routing to the protected endpoint. This issue has been fixed in versions 3.20.6.1, 3.27.3.1, 3.33.1.1, 3.35.1.1, 3.34.7, and 3.35.2.

Vulnerability class: Broken Access Control

EPSS: 0.005 (39.9th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 8.2 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N.

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-39852?
CVE-2026-39852 is a high-severity vulnerability in Quarkus, classified under Incorrect Authorization. CVSS score: 8.2/10. Published 2026-05-05.
How severe is CVE-2026-39852?
High severity. CVSS v3 base score is 8.2 out of 10.