Name: CVE-2026-21726: Improper Limitation of a Pathname to a Restricted Directory
Creator: Rapid7
Published: 2026-04-15T00:00:00.000Z
License: https://www.rapid7.com/legal/website-terms-of-use/
Keywords: CVE, CVE-2026-21726, CWE-22, CVSS 5.3, EPSS 0.00409

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.

CVSS Details

CVSS 3.1 Base Score: 5.3
CVSS 3.1 Vector: (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N)

Covered by Rapid7

Product	Vendor Advisory	Solution File	Added	Published
Redhat_linux	—	No solution exists	Jul 17, 2026	Apr 15, 2026

Prioritise with Active Threat Intelligence

With curated Threat Intelligence, you can see which vulnerabilities truly put you at risk, prioritize what matters most, and act before attackers do.

Explore Intelligence Hub

MDR Buyer's Guide

Global Threat Landscape Report

Grow your business

CVSS Details

Covered by Rapid7

Prioritise with Active Threat Intelligence