CVE-2026-42154

Name	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.
Source	CVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)

Vulnerable and fixed packages

The table below lists information on source packages.

Source Package	Release	Version	Status
prometheus (PTS)	bullseye	2.24.1+ds-1	vulnerable
	bookworm	2.42.0+ds-5	vulnerable
	trixie	2.53.3+ds1-2	vulnerable
	forky, sid	2.53.5+ds1-4	vulnerable

The information below is based on the following data on fixed versions.

Package	Type	Release	Fixed Version	Urgency	Origin	Debian Bugs
prometheus	source	(unstable)	(unfixed)

Notes

https://github.com/prometheus/prometheus/security/advisories/GHSA-8rm2-7qqf-34qm
https://github.com/prometheus/prometheus/pull/18584
https://github.com/prometheus/prometheus/pull/18585