{"id":"CVE-2026-21726","sourceIdentifier":"security@grafana.com","published":"2026-04-15T20:16:34.177","lastModified":"2026-06-17T13:20:05.657","vulnStatus":"Analyzed","cveTags":[],"descriptions":[{"lang":"en","value":"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."}],"affected":[{"source":"security@grafana.com","affectedData":[{"vendor":"Grafana","product":"Loki","defaultStatus":"unaffected","versions":[{"version":"2.3.0","lessThan":"3.5.9","versionType":"semver","status":"affected"}]}]}],"metrics":{"cvssMetricV31":[{"source":"security@grafana.com","type":"Secondary","cvssData":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N","baseScore":5.3,"baseSeverity":"MEDIUM","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"LOW","integrityImpact":"NONE","availabilityImpact":"NONE"},"exploitabilityScore":3.9,"impactScore":1.4}],"ssvcV203":[{"source":"134c704f-9b21-4f2e-91b3-4a467353bcc0","ssvcData":{"timestamp":"2026-04-15T20:01:24.769436Z","id":"CVE-2026-21726","options":[{"exploitation":"none"},{"automatable":"no"},{"technicalImpact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}]},"weaknesses":[{"source":"134c704f-9b21-4f2e-91b3-4a467353bcc0","type":"Secondary","description":[{"lang":"en","value":"CWE-22"}]}],"configurations":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:a:grafana:loki:*:*:*:*:*:*:*:*","versionEndExcluding":"3.6.4","matchCriteriaId":"4A927B56-3873-4166-8F65-6E312D898B03"}]}]}],"references":[{"url":"https://grafana.com/security/security-advisories/cve-2026-21726","source":"security@grafana.com","tags":["Vendor Advisory"]}]}