Vulnerability DatabaseCVE-2026-21726
Mend.io Vulnerability Database
The largest open source vulnerability database
What is a Vulnerability ID?
New vulnerability? Tell us about it!
CVE-2026-21726
Published:April 15, 2026
Updated:May 18, 2026
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.
Affected Packages
github.com/grafana/loki/v3 (GO):
Affected version(s) >=v3.0.0 <v3.6.4
Fix Suggestion:
Update to version v3.6.4
Related Resources (3)
https://grafana.com/security/security-advisories/cve-2026-21726
https://github.com/grafana/loki
https://nvd.nist.gov/vuln/detail/CVE-2026-21726
Do you need more information?
Contact Us
CVSS v4
Base Score:
6.9
Attack Vector
NETWORK
Attack Complexity
LOW
Attack Requirements
NONE
Privileges Required
NONE
User Interaction
NONE
Vulnerable System Confidentiality
LOW
Vulnerable System Integrity
NONE
Vulnerable System Availability
NONE
Subsequent System Confidentiality
NONE
Subsequent System Integrity
NONE
Subsequent System Availability
NONE
CVSS v3
Base Score:
5.3
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
LOW
Integrity
NONE
Availability
NONE
Weakness Type (CWE)
Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
CWE-22
URL Redirection to Untrusted Site ('Open Redirect')
CWE-601
EPSS
Base Score:
0.02