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.

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