CVE-2021-36156Network attack vector

File disclosure via traversable tenant-ID path

Published Aug 3, 2021 · Updated Aug 4, 2024

Path traversal in Grafana Loki 2.2.1 and earlier allows remote attackers to disclose portions of files via a crafted X-Scope-OrgID header. The ruler uses the header as a tenant ID to construct rule-file paths without rejecting traversal segments, then returns parsed file portions in error responses. Exploitation requires direct control of the header; a proxy that supplies and validates tenant IDs blocks this path, while process permissions bound the readable files.

CVSS severity5.3
Medium
EPSS probability1.48%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Path traversal in Grafana Loki 2.2.1 and earlier allows remote attackers to disclose portions of files via a crafted X-Scope-OrgID header. The ruler uses the header as a tenant ID to construct rule-file paths without rejecting traversal segments, then returns parsed file portions in error responses. Exploitation requires direct control of the header; a proxy that supplies and validates tenant IDs blocks this path, while process permissions bound the readable files.

The record

CVE
CVE-2021-36156
Published
Aug 3, 2021
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-22, T1005
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 3, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

5.3GitHub Advisory DatabaseCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-22Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
T1005Data from Local System

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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