CVE-2026-21726

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