What is CVE-2026-21729?

CVE-2026-21729 is a high-severity vulnerability in Grafana Loki, classified under Allocation of Resources Without Limits or Throttling. CVSS score: 7.5/10. Published 2026-07-16.

How severe is CVE-2026-21729?

High severity. CVSS v3 base score is 7.5 out of 10.

Resource exhaustion in Grafana Loki

CVE-2026-21729

Loki queries with large limits can cause large memory allocations which can impact the availability of the service, depending on its deployment strategy.

Published 2026-07-16 · last modified 2026-07-16.

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

EPSS exploit prediction

EPSS: 0.005 (38.9th percentile), scored 2026-10-24.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 39th percentile — 38.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.005 · newest: 0.005 · change: 0.000

Affected products

Grafana Loki — versions v3.0.0

Weakness classification (CWE)

CWE-770 — Allocation of Resources Without Limits or Throttling

References

grafana.com/security/security-advisories/cve-2026-21729 (vendor-advisory)

Frequently asked questions

What is CVE-2026-21729?: CVE-2026-21729 is a high-severity vulnerability in Grafana Loki, classified under Allocation of Resources Without Limits or Throttling. CVSS score: 7.5/10. Published 2026-07-16.
How severe is CVE-2026-21729?: High severity. CVSS v3 base score is 7.5 out of 10.