CVE-2026-21726Medium· 5.3▾ SunlitGrafana Loki Path Traversal - CVE-2021-36156 Bypass
▾ Sunlit zone — Low / medium · no exploitation signal
impact 29.2 · likelihood 0.1 · exploitation 0
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Exploit-prediction probability, daily snapshots since Jul 9.
Disclosure to exploitation, from the record and what we observed since indexing it.
Disclosed via OSV
0.4%
Last analysed / modified upstream
5.3 → —
medium → none
— → 5.3
none → medium
5.3 → —
medium → none
— → 5.3
none → medium
5.3 → —
medium → none
— → 5.3
none → medium
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.
github.com/grafana/loki/v3 < 3.6.4Upgrade to a patched release:
github.com/grafana/loki/v3 3.6.4Field changes observed since this record was first indexed.
Connected by shared product, vendor, weakness, or advisory.
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