GHSA-8rm2-7qqf-34qm

Prometheus: Remote read endpoint allows denial of service via crafted snappy payload

Source: GitHub Advisory Database (reviewed) High CVE-2026-42154

Packages

Ecosystem	Package	Affected	Fixed in
Go	github.com/prometheus/prometheus	>= 0.306.0, < 0.311.3	0.311.3
Go	github.com/prometheus/prometheus	< 0.305.2	0.305.2
Go	github.com/prometheus/prometheus	>= 1.0.0-rc.0, <= 2.5.0	no fix listed

Details

As written in the advisory (Markdown source, shown as plain text).

### Impact 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. ### Patches _Has the problem been patched? What versions should users upgrade to?_ Fixed in 3.11.3 and 3.5.3 LTS. Users should upgrade to these versions or later. ### Workarounds User who can not upgrade can place Prometheus behind a reverse proxy or firewall that requires authentication before requests reach /api/v1/read.

References

External links from the advisory. They lead to third-party sites.