GHSA-8rm2-7qqf-34qm Prometheus: Remote read endpoint allows denial of service via crafted snappy payload

• Go github.com/prometheus/prometheus: >= 0.306.0, < 0.311.3 → fixed in 0.311.3 • Go github.com/prometheus/prometheus: < 0.305.2 → fixed in 0.305.2 • Go github.com/prometheus/prometheus: >= 1.0.0-rc.0, <= 2.5.0 (no fix yet)

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.