CVE-2026-42154

Name: CVE-2026-42154
Creator: NVD / NIST
Published: 2026-05-04T19:16:04.397+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 7.5/10EPSS 0.56%

Last modified Jun 17, 2026

CVE-2026-42154 is a high-severity vulnerability rated 7.5/10 on the CVSS scale. 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. EPSS estimates a 0.56% chance of exploitation in the next 30 days.

Description

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.

Metrics

CVSS 3.1

7.5/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS Probability

0.56%

42.3th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Prometheus	Prometheus	< 3.5.3
Prometheus	Prometheus	>= 3.6.0, < 3.11.3

References

https://github.com/prometheus/prometheus/pull/18584Issue Tracking, Patch
https://github.com/prometheus/prometheus/pull/18585Issue Tracking, Patch
https://github.com/prometheus/prometheus/releases/tag/v3.11.3Release Notes
https://github.com/prometheus/prometheus/releases/tag/v3.5.3Release Notes
https://github.com/prometheus/prometheus/security/advisories/GHSA-8rm2-7qqf-34qmVendor Advisory

Timeline

Published: May 4, 2026
Last Modified: Jun 17, 2026
Status: Analyzed

Frequently Asked Questions

What is CVE-2026-42154?

How severe is CVE-2026-42154?

CVE-2026-42154 has a CVSS score of 7.5/10 (HIGH severity). The EPSS model estimates a 0.56% probability of exploitation in the next 30 days.

How do I fix CVE-2026-42154?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2026-42154?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST