CVE-2026-42154
Published: 04 May 2026
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…
more
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.
Likely Mitigating ControlsAI
Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.
Limiting concurrent sessions directly prevents uncontrolled resource consumption by capping the number of active sessions per user or account.
Analysis identifies uncontrolled resource consumption indicative of denial-of-service or abuse attempts.
Contingency plan testing includes resource exhaustion scenarios to verify recovery, making it harder for attackers to sustain exploits that cause uncontrolled consumption.
Updated contingency plans include current procedures to detect, contain, and recover from resource exhaustion, limiting an attacker's ability to sustain impact from uncontrolled consumption.
Alternate site allows resumption of operations if resource exhaustion at the primary site is exploited to cause unavailability.
Alternate telecommunications services enable resumption of essential functions when primary services become unavailable due to uncontrolled resource consumption.
The team can analyze and respond to resource exhaustion incidents, reducing the impact of attacks that exploit uncontrolled consumption weaknesses.
Timely maintenance support and spare parts enable rapid recovery from failures induced by uncontrolled resource consumption, shortening the impact window of denial-of-service attacks.
Security SummaryAI
CVE-2026-42154 is a memory allocation vulnerability in Prometheus, an open-source monitoring system and time series database. In versions prior to 3.5.3 and 3.11.3, the remote read endpoint (/api/v1/read) fails to validate the declared decoded length of a snappy-compressed request body before allocating heap memory. This flaw, linked to CWE-400 (Uncontrolled Resource Consumption) and CWE-789 (Memory Allocation with Excessive Size Value), carries a CVSS v3.1 base score of 7.5 (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H).
An unauthenticated remote attacker can exploit this vulnerability by sending a small, specially crafted snappy-compressed payload to the /api/v1/read endpoint. The invalid declared decoded length triggers a disproportionately large heap allocation per request. Under concurrent requests, this leads to rapid memory exhaustion, causing the Prometheus process to crash and potentially disrupting monitoring services.
Prometheus has addressed this issue in versions 3.5.3 and 3.11.3, with patches detailed in GitHub pull requests #18584 and #18585, release notes for those tags, and security advisory GHSA-8rm2-7qqf-34qm. Security practitioners should upgrade affected Prometheus instances to these patched versions and consider network restrictions on the remote read endpoint if immediate patching is not feasible.
Details
- CWE(s)
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
Remote unauthenticated exploitation of memory allocation flaw in Prometheus /api/v1/read endpoint directly enables application/system exploitation leading to DoS via heap exhaustion and crash.