{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-21726", "assignerOrgId": "57da9224-a3e2-4646-9d0e-c4dc2e05e7da", "state": "PUBLISHED", "assignerShortName": "GRAFANA", "dateReserved": "2026-01-05T09:26:06.215Z", "datePublished": "2026-04-15T19:24:31.268Z", "dateUpdated": "2026-04-15T20:01:33.375Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "57da9224-a3e2-4646-9d0e-c4dc2e05e7da", "shortName": "GRAFANA", "dateUpdated": "2026-04-15T19:24:31.268Z"}, "datePublic": "2026-04-15T19:20:00.780Z", "title": "Loki Path Traversal - CVE-2021-36156 Bypass", "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": [{"vendor": "Grafana", "product": "Loki", "platforms": ["OnPrem"], "defaultStatus": "unaffected", "versions": [{"version": "2.3.0", "status": "affected", "versionType": "semver", "lessThan": "3.5.9"}]}], "references": [{"url": "https://grafana.com/security/security-advisories/cve-2026-21726", "tags": ["vendor-advisory"]}], "metrics": [{"cvssV3_1": {"version": "3.1", "baseScore": 5.3, "baseSeverity": "MEDIUM", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N"}}], "source": {"discovery": "BUG_BOUNTY"}, "x_generator": {"engine": "cvelib 1.8.0"}}, "adp": [{"metrics": [{"other": {"type": "ssvc", "content": {"timestamp": "2026-04-15T20:01:24.769436Z", "id": "CVE-2026-21726", "options": [{"Exploitation": "none"}, {"Automatable": "no"}, {"Technical Impact": "partial"}], "role": "CISA Coordinator", "version": "2.0.3"}}}], "title": "CISA ADP Vulnrichment", "providerMetadata": {"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-04-15T20:01:33.375Z"}}]}}

{"dataType": "CVE_RECORD", "containers": {"adp": [{"title": "CISA ADP Vulnrichment", "metrics": [{"other": {"type": "ssvc", "content": {"id": "CVE-2026-21726", "role": "CISA Coordinator", "options": [{"Exploitation": "none"}, {"Automatable": "no"}, {"Technical Impact": "partial"}], "version": "2.0.3", "timestamp": "2026-04-15T20:01:24.769436Z"}}}], "providerMetadata": {"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-04-15T20:01:29.185Z"}}], "cna": {"title": "Loki Path Traversal - CVE-2021-36156 Bypass", "source": {"discovery": "BUG_BOUNTY"}, "metrics": [{"cvssV3_1": {"version": "3.1", "baseScore": 5.3, "baseSeverity": "MEDIUM", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N"}}], "affected": [{"vendor": "Grafana", "product": "Loki", "versions": [{"status": "affected", "version": "2.3.0", "lessThan": "3.5.9", "versionType": "semver"}], "platforms": ["OnPrem"], "defaultStatus": "unaffected"}], "datePublic": "2026-04-15T19:20:00.780Z", "references": [{"url": "https://grafana.com/security/security-advisories/cve-2026-21726", "tags": ["vendor-advisory"]}], "x_generator": {"engine": "cvelib 1.8.0"}, "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."}], "providerMetadata": {"orgId": "57da9224-a3e2-4646-9d0e-c4dc2e05e7da", "shortName": "GRAFANA", "dateUpdated": "2026-04-15T19:24:31.268Z"}}}, "cveMetadata": {"cveId": "CVE-2026-21726", "state": "PUBLISHED", "dateUpdated": "2026-04-15T20:01:33.375Z", "dateReserved": "2026-01-05T09:26:06.215Z", "assignerOrgId": "57da9224-a3e2-4646-9d0e-c4dc2e05e7da", "datePublished": "2026-04-15T19:24:31.268Z", "assignerShortName": "GRAFANA"}, "dataVersion": "5.2"}

{"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."}], "id": "CVE-2026-21726", "lastModified": "2026-04-15T20:16:34.177", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "NONE", "baseScore": 5.3, "baseSeverity": "MEDIUM", "confidentialityImpact": "LOW", "integrityImpact": "NONE", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N", "version": "3.1"}, "exploitabilityScore": 3.9, "impactScore": 1.4, "source": "security@grafana.com", "type": "Secondary"}]}, "published": "2026-04-15T20:16:34.177", "references": [{"source": "security@grafana.com", "url": "https://grafana.com/security/security-advisories/cve-2026-21726"}], "sourceIdentifier": "security@grafana.com", "vulnStatus": "Received"}

{}

{"affected": [{"configurations": [{"platform": ["onprem"], "status": "affected", "versions": {"scheme": "semver", "value": "[2.3.0,3.5.9)"}}], "enrichment": {"confidence": 100.0, "confidence_source": "matching", "scores": [{"score": 100.0, "source": "matching"}]}, "original": {"product": "Loki", "source": "cna", "vendor": "Grafana"}, "product": "loki", "vendor": "grafana"}], "created": "2026-04-15T21:30:13.802776+00:00", "updated": "2026-04-15T21:30:13.802881+00:00", "vendors": ["grafana", "grafana$PRODUCT$loki"]}