CVE-2026-21726

Severity CVSS v4.0:

Pending analysis

Type:

CWE-22 Path Traversal

Publication date:

15/04/2026

Last modified:

20/04/2026

Description

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}<br /> <br /> Thanks to Prasanth Sundararajan for reporting this vulnerability.

Impact

Vector 3.x

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N CVSS v3.1 Severity and Metrics:

Base Score: 5.30 MEDIUM
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

Attack Vector (AV): Network
Attack Complexity (AC): Low
Privileges Required (PR): None
User Interaction (UI): None
Scope (S): Unchanged
Confidentiality (C): Low
Integrity (I): None
Availability (A): None

Base Score 3.x

5.30

Severity 3.x

MEDIUM

Vulnerable products and versions

CPE	From	Up to
cpe:2.3:a:grafana:loki::::::::		3.6.4 (excluding)

To consult the complete list of CPE names with products and versions, see this page

References to Advisories, Solutions, and Tools

https://grafana.com/security/security-advisories/cve-2026-21726