CVE-2026-42154

Description

Prometheus is an open-source monitoring system and time series database. Prior to versions 3.5.3 and 3.11.3, the remote read endpoint (/api/v1/read) does not validate the declared decoded length in a snappy-compressed request body before allocating memory. An unauthenticated attacker can send a small payload that causes a huge heap allocation per request. Under concurrent load this can exhaust available memory and crash the Prometheus process. This issue has been patched in versions 3.5.3 and 3.11.3.

CVSS Vector

References

• https://github.com/prometheus/prometheus/pull/18584
• https://github.com/prometheus/prometheus/pull/18585
• https://github.com/prometheus/prometheus/releases/tag/v3.11.3
• https://github.com/prometheus/prometheus/releases/tag/v3.5.3
• https://github.com/prometheus/prometheus/security/advisories/GHSA-8rm2-7qqf-34qm