Prometheus: remote read endpoint allows denial of service via crafted snappy payload
CVE-2026-42154 is fixed in 5 products on 1 platform, first by DEBIAN-CVE-2026-42154, released May 4, 2026. It is not reported as exploited. Patch Radar priority: High.
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.
Where it's fixed
| Product | Fixed in | Fix | Released |
|---|---|---|---|
| Linux | |||
| amazon-cloudwatch-agent · amzn 2023 | 1.300066.2-2.amzn2023 | ALAS2023-2026-1747 | May 25, 2026 |
| flightctl · RHEL 10 | 1.1.3-1.el10em | RHSA-2026:41019 | May 22, 2026 |
| govulncheck-vulndb · opensuse-leap 16.0 | 0.0.20260723T184607-160000.1.1 | OPENSUSE-SU-2026:21483-1 | Jul 30, 2026 |
| opentelemetry-collector · RHEL 10 | 0.152.1-1.el10_0 | RHSA-2026:53413 | Jul 2, 2026 |
| opentelemetry-collector · RHEL 9 | 0:0.152.1-1.el9_8 | RHSA-2026:34359 | Jul 2, 2026 |
| opentelemetry-collector · almalinux 10 | 0.152.1-1.el10_2 | ALSA-2026:34357 | Jul 1, 2026 |
| opentelemetry-collector · almalinux 9 | 0.152.1-1.el9_8 | ALSA-2026:34359 | Jul 1, 2026 |
| opentelemetry-collector · rocky 10 | 0:0.152.1-1.el10_2 | RLSA-2026:34357 | Jul 7, 2026 |
| opentelemetry-collector · rocky 9 | 0:0.152.1-1.el9_8 | RLSA-2026:34359 | Jul 5, 2026 |
| prometheus · Debian 14 | 3.5.3+ds1-1 | DEBIAN-CVE-2026-42154 | May 4, 2026 |
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