CVE-2026-21726

mediumpriority · track · 0EPSS 0.004 · 35 %ileDEEURUUS
grimoire priorityP3 · Track
Exploitable?
—
no known exploitation
Likely / severe?
0.41% (35th) EPSS
CVSS 5.3 · medium
Is it mine?
8 products
Check your exposure
Who says so?
6 sources
cnnvd · enisa_euvd · fstec_bdu · osv

EPSS · scored 2026-10-27

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.

01

cvss

Technical severity, 0–10. One row per scoring source.

5.3
010

base score 0–10 · higher = more severe · hover a vector to decode

v3.15.3mediumAV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:Nsecondary · FSTEC (BDU) RU
v3.15.3mediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:Nsecondary · ENISA EU
v3.15.3mediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:Nsecondary · security@grafana.comexploitability 3.9 · impact 1.4
v3.15.3mediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:Nsecondary · OSV
v3.14.9mediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N/E:Usecondary · CVSS-BT (t0sche)
02

ssvc

A stakeholder decision — act, attend, or track — from exploitation and impact.

Trackcoordinatorcisa_ssvcUS
03

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-22USCWE-22USCWE-22USCWE-601US
04

affected products (8)

Products and version ranges known to be affected.

05

advisories (3)

Vendor and ecosystem advisories describing this.

  • WID-SEC-W-2026-0242Grafana Loki: Schwachstelle ermöglicht Offenlegung von InformationenDeutsch2026-01-27csaf · cert_bundDE

    Ein entfernter, anonymer Angreifer kann eine Schwachstelle in Grafana Loki ausnutzen, um Informationen offenzulegen.

  • GHSA-497x-rrr9-68jpGrafana Loki Path Traversal - CVE-2021-36156 Bypass2026-04-15ghsa · osvUS

    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.

  • GO-2026-5115Grafana Loki Path Traversal - CVE-2021-36156 Bypass in github.com/grafana/loki2026-06-25vendor · osvUS

    Grafana Loki Path Traversal - CVE-2021-36156 Bypass in github.com/grafana/loki

06

also known as (6)

Other names and identifiers for this entity.

07

sources

Which sources assert this record, and when.

cnnvdenisa_euvdfstec_bduosvcert_bundnvdNVDCVE.orgMITRE
published 2026-04-15modified 2026-10-26
08

references (5)

External citations — patches, advisories, analysis.

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