Prometheus: Remote read endpoint allows denial of service via crafted snappy payload
### 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.
describes (1)
Related CVEs.
| ID | severity | exploitable | ||
|---|---|---|---|---|
| CVE-2026-42154US | — | Exploit | ||
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… | ||||
references
External citations — patches, advisories, analysis.
- https://github.com/prometheus/prometheusPACKAGE
- https://github.com/prometheus/prometheus/pull/18584WEB
- https://github.com/prometheus/prometheus/pull/18585WEB
- https://github.com/prometheus/prometheus/releases/tag/v3.11.3WEB
- https://github.com/prometheus/prometheus/releases/tag/v3.5.3WEB
- https://github.com/prometheus/prometheus/security/advisories/GHSA-8rm2-7qqf-34qmWEB
- https://nvd.nist.gov/vuln/detail/CVE-2026-42154ADVISORY
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