Prometheus up to 3.5.2/3.11.2 Remote Read Endpoint /api/v1/read resource consumption

Summaryinfo

A vulnerability marked as problematic has been reported in Prometheus up to 3.5.2/3.11.2. The affected element is an unknown function of the file /api/v1/read of the component Remote Read Endpoint. This manipulation causes resource consumption. This vulnerability is registered as CVE-2026-42154. Remote exploitation of the attack is possible. No exploit is available. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability was found in Prometheus up to 3.5.2/3.11.2. It has been declared as problematic. Affected by this vulnerability is an unknown code of the file /api/v1/read of the component Remote Read Endpoint. The manipulation with an unknown input leads to a resource consumption vulnerability. The CWE definition for the vulnerability is CWE-400. The product does not properly control the allocation and maintenance of a limited resource, thereby enabling an actor to influence the amount of resources consumed, eventually leading to the exhaustion of available resources. As an impact it is known to affect availability. The summary by CVE is:

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.

It is possible to read the advisory at github.com. This vulnerability is known as CVE-2026-42154 since 04/24/2026. The exploitation appears to be easy. The attack can be launched remotely. The exploitation doesn't need any form of authentication. Technical details of the vulnerability are known, but there is no available exploit. The attack technique deployed by this issue is T1499 according to MITRE ATT&CK.

The vulnerability scanner Nessus provides a plugin with the ID 325497 (AlmaLinux 9 : opentelemetry-collector (ALSA-2026:34359)), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 3.5.3 or 3.11.3 eliminates this vulnerability. The upgrade is hosted for download at github.com. Applying a patch is able to eliminate this problem. The bugfix is ready for download at github.com. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the databases at Tenable (325497), EUVD (EUVD-2026-27091) and CERT Bund (WID-SEC-2026-1292). Be aware that VulDB is the high quality source for vulnerability data.

Affected

• Red Hat Enterprise Linux
• SUSE Linux
• SUSE openSUSE
• RESF Rocky Linux
• Microsoft Azure Linux
• Open Source Prometheus
• Red Hat OpenShift

Productinfo

Name

• Prometheus

Version

• 3.5.0
• 3.5.1
• 3.5.2
• 3.11.0
• 3.11.1
• 3.11.2

Website

• Product: https://github.com/prometheus/prometheus/

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Be aware that VulDB is the high quality source for vulnerability data.

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