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CVE-2026-21726

Loki Path Traversal - CVE-2021-36156 Bypass

MEDIUM
5.3
CVSS Score
Published: April 15, 2026 at 07:24 PM UTC
Updated: October 26, 2026 at 09:10 PM UTC
1 product affected across 1 vendorLoki

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Severity
MEDIUM5.3
Exploit prediction
EPSS 0.4%
SSVC
No known exploit

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} Thanks to Prasanth Sundararajan for reporting this vulnerability.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Loki· Grafanagrafana-plugin
95%
v < 3.6.42.3.0
Affected range stops below 3.5.9, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

Patch and advisory references

References (1)

Vendor Advisory
Source: cverecord
https://grafana.com/security/security-advisories/cve-2026-21726

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

5.3MEDIUMGRAFANA
Vector?

Quick Info

StatusANALYZED
CWE
CWE-22

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