Medium
Loki Path Traversal - CVE-2021-36156 Bypass
Type: advisorySources: OSV
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.
- Products
- Not specified
- Affected versions
- Not specified
- Fixed versions
- Not specified
- CVEs
- CVE-2026-21726
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 4 Nov 2026, 16:48 UTC · Revision 1
Source evidence
Loki Path Traversal - CVE-2021-36156 Bypass
core-osv · Original sourcePublished 15 Apr 2026, 19:24 UTC
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.
osv:CVE-2026-21726
Complete source record
{
"id": "a469282359cbcee603da5352601419effe01aa7cd040b1a8bdbfbaaa93bea4c7",
"url": "https://osv.dev/vulnerability/CVE-2026-21726",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "Loki Path Traversal - CVE-2021-36156 Bypass",
"summary": "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.",
"evidence": "osv:CVE-2026-21726",
"products": [],
"severity": "medium",
"structured": {
"id": "CVE-2026-21726",
"aliases": [
"CVE-2026-21726",
"GHSA-497x-rrr9-68jp",
"GO-2026-5115"
],
"metrics": [
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N"
}
],
"affected": [
{
"ranges": [
{
"repo": "https://github.com/grafana/loki",
"type": "GIT",
"events": [
{
"introduced": "0"
},
{
"fixed": "d80526692af3bf28c35622a59a3231933b193bc2"
}
],
"database_specific": {
"extracted_events": [
{
"cpe": "cpe:2.3:a:grafana:loki:*:*:*:*:*:*:*:*",
"range": [
{
"introduced": "0"
},
{
"fixed": "3.6.4"
}
],
"source": "CPE_RANGE"
}
]
}
}
],
"versions": [
"v3.6.3",
"v3.6.2",
"v3.6.1",
"v3.6.0",
"helm-loki-6.43.0",
"helm-loki-6.42.0",
"helm-loki-6.41.1",
"helm-loki-6.41.0",
"helm-loki-6.40.0",
"helm-loki-6.39.0",
"helm-loki-6.38.0",
"helm-loki-6.37.0",
"helm-loki-6.36.1",
"helm-loki-6.36.0",
"helm-loki-6.35.1",
"helm-loki-6.35.0",
"helm-loki-6.34.0",
"helm-loki-6.33.0",
"helm-loki-6.32.0",
"helm-loki-6.31.0",
"helm-loki-6.30.1",
"helm-loki-6.29.0",
"operator/v0.8.0",
"helm-loki-6.28.0",
"helm-loki-6.27.0",
"helm-loki-6.26.0",
"helm-loki-6.25.1",
"helm-loki-6.25.0",
"helm-loki-6.24.1",
"helm-loki-6.24.0",
"helm-loki-6.23.0",
"helm-loki-6.22.0",
"helm-loki-6.21.0",
"helm-loki-6.20.0",
"operator/v0.7.1",
"helm-loki-6.19.0",
"pkg/logql/syntax/v0.0.1",
"operator/v0.7.0",
"helm-loki-6.18.0",
"helm-loki-6.16.0",
"operator/v0.6.2",
"helm-loki-6.12.0",
"helm-loki-6.11.0",
"helm-loki-6.10.2",
"helm-loki-6.10.1",
"helm-loki-6.10.0",
"helm-loki-6.9.0",
"helm-loki-6.8.0",
"helm-loki-6.7.4",
"helm-loki-6.7.3",
"helm-loki-6.7.2",
"helm-loki-6.7.1",
"helm-loki-6.7.0",
"helm-loki-6.6.6",
"helm-loki-6.6.5",
"helm-loki-6.6.4",
"helm-loki-6.6.3",
"operator/v0.6.1",
"helm-loki-6.6.2",
"helm-loki-6.6.1",
"helm-loki-6.6.0",
"helm-loki-6.5.2",
"helm-loki-6.5.1",
"helm-loki-5.47.2",
"helm-loki-6.5.0",
"helm-loki-6.4.2",
"helm-loki-6.4.1",
"helm-loki-6.4.0",
"helm-loki-6.3.3",
"helm-loki-6.3.4",
"helm-loki-6.3.2",
"helm-loki-6.3.1",
"helm-loki-6.3.0",
"helm-loki-6.2.5",
"helm-loki-6.2.4",
"helm-loki-6.2.3",
"helm-loki-6.2.2",
"helm-loki-6.2.1",
"helm-loki-6.2.0",
"helm-loki-6.1.0",
"helm-loki-6.0.0",
"operator/v0.6.0",
"helm-loki-5.47.1",
"helm-loki-5.47.0",
"helm-loki-5.46.0",
"helm-loki-5.45.0",
"helm-loki-5.44.4",
"helm-loki-5.44.3",
"helm-loki-5.44.2",
"helm-loki-5.44.1",
"helm-loki-5.44.0",
"helm-loki-5.43.7",
"helm-loki-5.43.6",
"helm-loki-5.43.5",
"helm-loki-5.43.4",
"helm-loki-5.43.3",
"helm-loki-5.43.2",
"helm-loki-5.43.1",
"helm-loki-5.43.0",
"helm-loki-5.42.3",
"helm-loki-5.42.2",
"helm-loki-5.42.1",
"helm-loki-5.42.0",
"helm-loki-5.41.8",
"helm-loki-5.41.7",
"helm-loki-5.41.6",
"helm-loki-5.41.5",
"helm-loki-5.41.4",
"helm-loki-5.41.3",
"helm-loki-5.41.2",
"helm-loki-5.41.1",
"helm-loki-5.41.0",
"helm-loki-5.40.1",
"helm-loki-5.39.0",
"helm-loki-5.38.0",
"helm-loki-5.37.0",
"helm-loki-5.36.3",
"helm-loki-5.36.2",
"helm-loki-5.36.1",
"helm-loki-5.36.0",
"operator/v0.5.0",
"helm-loki-5.35.0",
"helm-loki-5.34.0",
"helm-loki-5.33.0",
"helm-loki-5.32.0",
"helm-loki-5.31.0",
"helm-loki-5.30.0",
"helm-loki-5.29.0",
"helm-loki-5.28.0",
"helm-loki-5.27.0",
"helm-loki-5.26.0",
"helm-loki-5.25.0",
"helm-loki-5.24.0",
"helm-loki-5.23.1",
"helm-loki-5.23.0",
"helm-loki-5.22.2",
"helm-loki-5.22.1",
"helm-loki-5.22.0",
"helm-loki-5.21.0",
"helm-loki-5.20.0",
"helm-loki-5.19.0",
"helm-loki-5.18.1",
"helm-loki-5.18.0",
"helm-loki-5.17.0",
"helm-loki-5.15.0",
"helm-loki-5.14.1",
"helm-loki-5.14.0",
"helm-loki-5.13.0",
"helm-loki-5.12.0",
"helm-loki-5.11.0",
"helm-loki-5.10.0",
"operator/v0.4.0",
"helm-loki-5.9.2",
"helm-loki-5.9.1",
"helm-loki-5.9.0",
"helm-loki-5.8.11",
"helm-loki-5.8.10",
"helm-loki-5.8.9",
"helm-loki-5.8.8",
"helm-loki-5.8.7",
"helm-loki-5.8.6",
"helm-loki-5.8.5",
"helm-loki-5.8.4",
"helm-loki-5.8.3",
"helm-loki-5.8.2",
"helm-loki-5.8.1",
"helm-loki-5.8.0",
"helm-loki-5.7.1",
"helm-loki-5.6.4",
"helm-loki-5.6.3",
"helm-loki-5.6.2",
"helm-loki-5.6.1",
"helm-loki-5.6.0",
"helm-loki-5.5.10",
"helm-loki-5.5.12",
"helm-loki-5.5.11",
"helm-loki-5.5.9",
"helm-loki-5.5.8",
"helm-loki-5.5.7",
"helm-loki-5.5.6",
"helm-loki-5.5.5",
"helm-loki-5.5.4",
"helm-loki-5.5.3",
"helm-loki-5.5.2",
"helm-loki-5.5.1",
"helm-loki-5.5.0",
"helm-loki-5.4.0",
"helm-loki-5.3.1",
"helm-loki-5.3.0",
"helm-loki-5.2.0",
"helm-loki-5.1.0",
"helm-loki-5.0.0",
"helm-loki-4.10.0",
"helm-loki-4.9.0",
"helm-loki-4.8.0",
"helm-loki-4.7.0",
"helm-loki-4.6.2",
"helm-loki-4.6.1",
"helm-loki-4.6.0",
"helm-loki-4.5.1",
"helm-loki-4.5.0",
"helm-loki-4.4.2",
"helm-loki-4.4.1",
"helm-loki-4.4.0",
"helm-loki-4.3.0",
"helm-loki-4.2.0",
"helm-loki-4.1.0",
"helm-loki-4.0.0",
"helm-loki-3.10.0",
"helm-loki-3.9.0",
"helm-loki-3.8.2",
"helm-loki-3.8.1",
"helm-loki-3.8.0",
"helm-loki-3.7.0",
"helm-loki-3.6.1",
"helm-loki-3.6.0",
"helm-loki-3.5.0",
"helm-loki-3.4.3",
"helm-loki-3.4.2",
"helm-loki-3.4.1",
"helm-loki-3.4.0",
"helm-loki-3.3.4",
"helm-loki-3.3.3",
"helm-loki-3.3.2",
"helm-loki-3.3.1",
"helm-loki-3.3.0",
"helm-loki-3.2.2",
"helm-loki-3.2.1",
"helm-loki-3.2.0",
"helm-loki-3.1.0",
"helm-loki-3.0.9",
"helm-loki-3.0.8",
"helm-loki-3.0.7",
"helm-loki-3.0.6",
"helm-loki-3.0.5",
"helm-loki-3.0.4",
"helm-loki-3.0.3",
"helm-loki-3.0.2",
"helm-loki-3.0.1",
"helm-loki-3.0.0",
"v2.0.0",
"v1.6.0",
"v1.5.0",
"v1.3.0",
"v1.2.0",
"v1.1.0",
"v1.0.0",
"v0.4.0",
"v0.3.0",
"v0.2.0",
"v1.0.1",
"v0.1.0"
],
"database_specific": {
"source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-21726.json"
}
}
],
"modified": "2026-10-28T02:30:37.395783583Z",
"provider": "osv",
"references": [
"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/21xxx/CVE-2026-21726.json",
"https://grafana.com/security/security-advisories/cve-2026-21726",
"https://nvd.nist.gov/vuln/detail/CVE-2026-21726"
],
"provider_metadata": {
"cna_assigner": "GRAFANA",
"unresolved_ranges": [
{
"extracted_events": [
{
"range": [
{
"introduced": "2.3.0"
},
{
"fixed": "3.5.9"
}
],
"source": "AFFECTED_FIELD",
"strategy": "StandardRange"
}
]
}
],
"osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/21xxx/CVE-2026-21726.json"
}
},
"related_cves": [
{
"value": "CVE-2026-21726",
"evidence": "/id"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 504865,
"published_at": "2026-04-15T19:24:31.268+00:00"
}