CVE-2026-21726 MEDIUM

CVE-2026-21726: Loki Path Traversal - CVE-2021-36156 Bypass

Vendor Grafana
Product Loki
Published April 15, 2026
Last update June 12, 2026

CVSS base score

5.3/10
Attack vector Network
Attack complexity Low
Privileges required None
User interaction None
Confidentiality Low
Integrity None

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

What the vulnerability does

01Description

The CVE-2021-36156 fix validates the namespace parameter for path traversal sequences after a single URL decode, by double encoding, an attacker can read files at the Ruler API endpoint /loki/api/v1/rules/{namespace} Thanks to Prasanth Sundararajan for reporting this vulnerability.

Key dates

02Disclosure timeline

April 15, 2026 CVE published
June 12, 2026 Record updated