{"cve":"CVE-2026-21726","nvd":{"published":"2026-04-15T20:16:34.177","modified":"2026-10-26T21:10:00.170","status":"Analyzed","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}\n\nThanks to Prasanth Sundararajan for reporting this vulnerability.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N","score":5.3},"cwes":["CWE-22"],"references":["https://grafana.com/security/security-advisories/cve-2026-21726"],"products":["grafana:loki"],"source":"nvd","synced_at":"2026-10-26T21:38:48.864438205+00:00"},"epss":{"cve":"CVE-2026-21726","score":0.00409,"percentile":0.34945,"date":"2026-10-26"},"kev":null,"osv":[{"id":"GHSA-497x-rrr9-68jp","url":"https://osv.dev/vulnerability/GHSA-497x-rrr9-68jp","summary":"Grafana Loki Path Traversal - CVE-2021-36156 Bypass","modified":"2026-09-10T03:51:00.938890119Z","packages":[{"ecosystem":"Go","name":"github.com/grafana/loki/v3","purl":"pkg:golang/github.com/grafana/loki/v3","ranges":["<3.6.4"],"fixed":["3.6.4"]}]},{"id":"GO-2026-5115","url":"https://osv.dev/vulnerability/GO-2026-5115","summary":"Grafana Loki Path Traversal - CVE-2021-36156 Bypass in github.com/grafana/loki","modified":"2026-07-07T22:59:27.802062523Z","packages":[{"ecosystem":"Go","name":"github.com/grafana/loki","purl":"pkg:golang/github.com/grafana/loki","ranges":["all versions"],"fixed":[]},{"ecosystem":"Go","name":"github.com/grafana/loki/v3","purl":"pkg:golang/github.com/grafana/loki/v3","ranges":["<3.6.4"],"fixed":["3.6.4"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}