Path traversal in Loki - CVE-2026-21726
Published: January 30, 2026
Vulnerability identifier: #VU122161
CSH Severity: Medium
CVSS v4: 6.9 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-21726
CWE-ID: CWE-22
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to perform directory traversal attacks.
The vulnerability exists due to input validation error when processing directory traversal sequences within the "/loki/api/v1/rules/{namespace}" API endpoint. A remote attacker can send a specially crafted HTTP request and read arbitrary files on the system.
Note, the vulnerability exists due to incomplete fix for #VU64412 (CVE-2021-36156).
Affected software
Loki
How to mitigate CVE-2026-21726
Install updates from vendor's website.
Loki - update to 3.6.4