---
id: CVE-2026-42154
title: Prometheus is an open-source monitoring system and time series database
summary: >-
  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…
severity: high
cvss: 7.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'
cwe:
  - CWE-400
  - CWE-789
  - CWE-770
vendor: prometheus
product: prometheus
affected:
  - prometheus < 3.5.3
  - 'prometheus >= 3.6.0, < 3.11.3'
patched:
  - prometheus 3.11.3
published: '2026-05-04'
updated: '2026-09-10'
sourceUpdated: '2026-09-10T13:20:07.003'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-42154'
references:
  - url: 'https://github.com/prometheus/prometheus/pull/18584'
    label: security-advisories@github.com
  - url: 'https://github.com/prometheus/prometheus/pull/18585'
    label: security-advisories@github.com
  - url: 'https://github.com/prometheus/prometheus/releases/tag/v3.11.3'
    label: security-advisories@github.com
  - url: 'https://github.com/prometheus/prometheus/releases/tag/v3.5.3'
    label: security-advisories@github.com
  - url: >-
      https://github.com/prometheus/prometheus/security/advisories/GHSA-8rm2-7qqf-34qm
    label: security-advisories@github.com
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    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://access.redhat.com/security/cve/CVE-2026-42154'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2466505'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: >-
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    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
tags:
  - nvd
  - cve.org
  - exploit-available
ssvc:
  exploitation: none
  automatable: 'yes'
  technicalImpact: partial
  timestamp: '2026-05-04T20:18:48.754025Z'
epss: 0.00893
epssPercentile: 0.57752
exploits:
  github: 1
  githubRepos:
    - 'https://github.com/ShadowByte1/CVE-2026-42154'
  checkedAt: '2026-09-26T09:05:43.688Z'
exploitAvailable: true
ingestedAt: '2026-07-01T15:50:58.801Z'
---

## Overview

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.

## Affected

- `prometheus < 3.5.3`
- `prometheus >= 3.6.0, < 3.11.3`

## Remediation

Upgrade past the affected range:

- `prometheus 3.11.3`