CVE-2026-42154: Prometheus denial of service via memory exhaustion in remote read endpoint

CVE-2026-42154 · Severity: high · CVSS 7.5 · Published 2026-05-04

Prometheus, a widely used open-source monitoring and alerting system, is vulnerable to a denial-of-service attack. An attacker can send a specially crafted, small request to the system's data reading interface that forces the server to allocate massive amounts of memory. This can lead to memory exhaustion and cause the monitoring service to crash, potentially leaving infrastructure unmonitored.

Technologies: github.com/prometheus/prometheus (Go), Prometheus. Vendors: Go, Prometheus.

Quick answers

Is CVE-2026-42154 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-42154 being exploited in the wild.
How severe is CVE-2026-42154?
High severity, with a CVSS score of 7.5, published 4 May 2026.
Which products and versions are affected?
github.com/prometheus/prometheus (Go) SEMVER:introduced=0,fixed=0.305.2,introduced=0.306.0,fixed=0.311.3,introduced=1.0.0-rc.0, SEMVER:introduced=0.306.0,fixed=0.311.3; github.com/prometheus/prometheus/v2 (Go) SEMVER:introduced=0; Prometheus < 3.5.3, >= 3.6.0 < 3.11.3, >= 0.306.0, < 0.311.3; < 0.305.2; >= 1.0.0-rc.0, <= 2.5.0.
Is there a fix for CVE-2026-42154?
Yes. github.com/prometheus/prometheus (Go): upgrade to 0.311.3 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-42154 attacked?
It is attacked over the network, in a software library.
Am I affected by CVE-2026-42154?
Check whether you run github.com/prometheus/prometheus (Go), github.com/prometheus/prometheus/v2 (Go) or Prometheus at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

  • github.com/prometheus/prometheus (Go): upgrade to 0.311.3 or later
    go get github.com/prometheus/prometheus@v0.311.3

Technical details

A resource exhaustion vulnerability exists in the Prometheus remote read endpoint (/api/v1/read). The component fails to validate the declared decoded length of snappy-compressed request bodies before performing memory allocation. An unauthenticated remote attacker can exploit this by sending a small, malicious payload that specifies a massive decoded size, leading to large heap allocations. Under concurrent load, this results in memory exhaustion and a process crash (DoS). The issue is addressed in versions 3.5.3 and 3.11.3 by implementing a decode limit.

Affected products

  • Prometheus Prometheus < 3.5.3, >= 3.6.0 < 3.11.3

Identifiers

  • CVE-2026-42154
  • GHSA-8rm2-7qqf-34qm
  • GO-2026-5264

Timeline

  • 2026-04-27: patched: Fixes merged and releases 3.5.3 and 3.11.3 published.
  • 2026-04-27: advisory: GitHub Security Advisory GHSA-8rm2-7qqf-34qm published.
  • 2026-05-04: disclosed: NVD publication date.

References

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