How severe is CVE-2021-36156?

CVE-2021-36156 has a CVSS 3.x base score of 5.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity none, and availability none.

Is CVE-2021-36156 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (74th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-36156?

CVE-2021-36156 affects Grafana Loki. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-36156?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2021-36156 published?

CVE-2021-36156 was published on 2021-08-03 and last updated on 2026-06-17.

CVE-2021-36156

CVE-2021-36156 is a medium-severity vulnerability in Grafana Loki with a CVSS 3.x base score of 5.3. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-22.

Key facts

Severity: Medium (CVSS 3.x base score 5.3)
CVSS v2: 5.0
EPSS exploit prediction: 1% (74th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-22
Affected product: Grafana Loki
Published: 2021-08-03
Last modified: 2026-06-17

Description

An issue was discovered in Grafana Loki through 2.2.1. The header value X-Scope-OrgID is used to construct file paths for rules files, and if crafted to conduct directory traversal such as ae ../../sensitive/path/in/deployment pathname, then Loki will attempt to parse a rules file at that location and include some of the contents in the error message.

Frequently asked questions

What is CVE-2021-36156?: An issue was discovered in Grafana Loki through 2.2.1. The header value X-Scope-OrgID is used to construct file paths for rules files, and if crafted to conduct directory traversal such as ae ../../sensitive/path/in/deployment pathname, then Loki will attempt to parse a rules file at that location and include some of the contents in the error message.
How severe is CVE-2021-36156?: CVE-2021-36156 has a CVSS 3.x base score of 5.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity none, and availability none.
Is CVE-2021-36156 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (74th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-36156?: CVE-2021-36156 affects Grafana Loki. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-36156?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-36156 published?: CVE-2021-36156 was published on 2021-08-03 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:grafana:loki:*:*:*:*:*:*:*:*

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