Heap Exhaustion via Unvalidated Len in Prometheus Remote Read (<3.5.3/3.11.3)
CVE-2026-42154 Published on May 4, 2026
Prometheus: remote read endpoint allows denial of service via crafted snappy payload
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.
Vulnerability Analysis
CVE-2026-42154 is exploitable with network access, and does not require authorization privileges or user interaction. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to have no impact on confidentiality and integrity, and a high impact on availability.
Weakness Types
What is a Resource Exhaustion Vulnerability?
The software 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.
CVE-2026-42154 has been classified to as a Resource Exhaustion vulnerability or weakness.
What is a Stack Exhaustion Vulnerability?
The product allocates memory based on an untrusted, large size value, but it does not ensure that the size is within expected limits, allowing arbitrary amounts of memory to be allocated.
CVE-2026-42154 has been classified to as a Stack Exhaustion vulnerability or weakness.
Allocation of Resources Without Limits or Throttling
The software allocates a reusable resource or group of resources on behalf of an actor without imposing any restrictions on the size or number of resources that can be allocated, in violation of the intended security policy for that actor.
Products Associated with CVE-2026-42154
You can be notified by email with stack.watch whenever vulnerabilities like CVE-2026-42154 are published in these products:
Affected Versions
prometheus:- Version < 3.5.3 is affected.
- Version >= 3.6.0, < 3.11.3 is affected.
- Version 0:0.152.1-1.el10_2 and below * is unaffected.
- Version 0:0.152.1-1.el9_8 and below * is unaffected.
- Version 0:1.0.3-1.el9em and below * is unaffected.
- Version 0:1.1.3-1.el10em and below * is unaffected.
- Version 0:1.1.3-1.el9em and below * is unaffected.
- Version 1784747884 and below * is unaffected.
- Version 1784747816 and below * is unaffected.
- Version 1784747815 and below * is unaffected.
- Version 1782405469 and below * is unaffected.
- Version 1784562060 and below * is unaffected.
- Version 1784906628 and below * is unaffected.
- Version 1782374537 and below * is unaffected.
- Version 1783502022 and below * is unaffected.
- Version 1783502465 and below * is unaffected.
- Version 1783502025 and below * is unaffected.
- Version 1783502494 and below * is unaffected.
- Version 1783502401 and below * is unaffected.
- Version 1783502403 and below * is unaffected.
- Version 1783502022 and below * is unaffected.
- Version 1783502023 and below * is unaffected.
- Version 1783502029 and below * is unaffected.
- Version 1783502445 and below * is unaffected.
- Version 1784194638 and below * is unaffected.
- Version 1784194353 and below * is unaffected.
- Version 1784196588 and below * is unaffected.
- Version 1784195620 and below * is unaffected.
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- Version 1784194144 and below * is unaffected.
- Version 1784194980 and below * is unaffected.
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- Version 1784194971 and below * is unaffected.
- Version 1784128388 and below * is unaffected.
- Version 1784128860 and below * is unaffected.
- Version 1784126780 and below * is unaffected.
- Version 1784127787 and below * is unaffected.
- Version 1784126762 and below * is unaffected.
- Version 1784127762 and below * is unaffected.
- Version 1784126832 and below * is unaffected.
- Version 1784126774 and below * is unaffected.
- Version 1784127791 and below * is unaffected.
- Version 1784127135 and below * is unaffected.
- Version 1784126733 and below * is unaffected.
- Version 1784127775 and below * is unaffected.
- Version 2.19.0-1.hum1 and below * is unaffected.
- Version 0.153.0-1.hum1 and below * is unaffected.
- Version 0.155.0-0.1.hum1 and below * is unaffected.
- Version 1784060681 and below * is unaffected.
- Version 1784561376 and below * is unaffected.
- Version 1784583836 and below * is unaffected.
- Version 1784349713 and below * is unaffected.
- Version 1784053555 and below * is unaffected.
- Version 1782859326 and below * is unaffected.
- Version 1783750447 and below * is unaffected.
- Version 1783751865 and below * is unaffected.
- Version 1784353904 and below * is unaffected.
- Version 1784351966 and below * is unaffected.
- Version 1783955846 and below * is unaffected.
- Version 1784125838 and below * is unaffected.
- Version 1783968861 and below * is unaffected.
- Version 1783968861 and below * is unaffected.
- Version 1783968468 and below * is unaffected.
- Version 1783960127 and below * is unaffected.
- Version 1783968861 and below * is unaffected.
- Version 1783968861 and below * is unaffected.
Exploit Probability
EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.