CVE-2026-42154
HIGH7.5EPSS 0.02%Prometheus: Remote read endpoint allows denial of service via crafted snappy payload
Description
### 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.
Affected packages (3)
- Bitnami/prometheusfrom 0, < 3.5.3, >= 3.6.0, < 3.11.3
- Debian/prometheusfrom 0
- Go/github.com/prometheus/prometheusfrom 0, < 0.311.3
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 3.1 | HIGH7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
References (8)
- ADVISORYhttps://nvd.nist.gov/vuln/detail/CVE-2026-42154
- ADVISORYhttps://security-tracker.debian.org/tracker/CVE-2026-42154
- PATCHhttps://github.com/prometheus/prometheus
- WEBhttps://github.com/prometheus/prometheus/pull/18584
- WEBhttps://github.com/prometheus/prometheus/pull/18585
- WEBhttps://github.com/prometheus/prometheus/releases/tag/v3.11.3
- WEBhttps://github.com/prometheus/prometheus/releases/tag/v3.5.3
- WEBhttps://github.com/prometheus/prometheus/security/advisories/GHSA-8rm2-7qqf-34qm