CVE-2026-42154: Prometheus Denial of Service Vulnerability
HIGHCVE-2026-42154 is a HIGH (CVSS 7.5) denial of service vulnerability (CWE-789: Memory Allocation with Excessive Size Value) affecting Prometheus libraries in the Go ecosystem. The issue involves remote read endpoint allows denial of service via crafted snappy payload. Remediation is available by upgrading affected packages to version 0.311.3, 0.305.2.
CVE-2026-42154 at a Glance
Security Impact
CVSS: 7.5
The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H).
How to Fix CVE-2026-42154
To remediate this vulnerability, upgrade all affected Prometheus dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.
Upgrade github.com/prometheus/prometheus to 0.311.3Upgrade github.com/prometheus/prometheus to 0.305.2Upgrade github.com/prometheus/prometheus to Latest secure releaseRun the following command in your project directory to verify that all resolved dependencies use the patched release:
inspect dependencies for github.com/prometheus/prometheusHow to Check if You Are Affected
To determine whether your application is affected by CVE-2026-42154, inspect your project dependencies for Prometheus:
inspect dependencies for github.com/prometheus/prometheusAnalyze the terminal output to locate any version of Prometheus in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 0.311.3), your application is affected.
Note: Verify declared build manifests and deployed runtime container environments.
Technical Details
Vulnerability Mechanism & Technical Analysis
This vulnerability is classified under CWE-789: Memory Allocation with Excessive Size Value, where 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. In Prometheus, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.
Source Advisory Statement
CVE-2026-42154 Affected Prometheus Versions
3 component(s)| Product / Package | Ecosystem | Affected Versions | Fixed Version |
|---|---|---|---|
|
github.com/prometheus/prometheus
|
Go |
≥ 0.306.0
< 0.311.3
|
0.311.3
|
|
github.com/prometheus/prometheus
|
Go |
< 0.305.2
|
0.305.2
|
|
github.com/prometheus/prometheus
|
Go |
≥ 1.0.0-rc.0
≤ 2.5.0
|
|
References
Frequently Asked Questions
What is CVE-2026-42154?
Which Prometheus versions are affected?
What version fixes CVE-2026-42154?
Is github.com/prometheus/prometheus affected?
What is the CVSS score of CVE-2026-42154?
What CWE is associated with CVE-2026-42154?
How can I check Go dependencies for CVE-2026-42154?
Machine-readable OSV JSON
OSV v1.5 Schema
{
"schema_version" : "1.4.0",
"id" : "GHSA-8rm2-7qqf-34qm",
"modified" : "2026-06-08T16:22:14Z",
"published" : "2026-05-05T19:34:05Z",
"aliases" : [ "CVE-2026-42154" ],
"summary" : "Prometheus: Remote read endpoint allows denial of service via crafted snappy payload",
"details" : "### Impact\n\nThe remote read endpoint (`/api/v1/read`) does not validate the declared decoded length in a snappy-compressed request body before allocating memory.\nAn 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.\n\n### Patches\n_Has the problem been patched? What versions should users upgrade to?_\n\nFixed in 3.11.3 and 3.5.3 LTS. Users should upgrade to these versions or later.\n\n### Workarounds\nUser who can not upgrade can place Prometheus behind a reverse proxy or firewall that requires authentication before requests reach /api/v1/read.",
"severity" : [ {
"type" : "CVSS_V3",
"score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"
} ],
"affected" : [ {
"package" : {
"ecosystem" : "Go",
"name" : "github.com/prometheus/prometheus"
},
"ranges" : [ {
"type" : "ECOSYSTEM",
"events" : [ {
"introduced" : "0.306.0"
}, {
"fixed" : "0.311.3"
} ]
} ]
}, {
"package" : {
"ecosystem" : "Go",
"name" : "github.com/prometheus/prometheus"
},
"ranges" : [ {
"type" : "ECOSYSTEM",
"events" : [ {
"introduced" : "0"
}, {
"fixed" : "0.305.2"
} ]
} ]
}, {
"package" : {
"ecosystem" : "Go",
"name" : "github.com/prometheus/prometheus"
},
"ranges" : [ {
"type" : "ECOSYSTEM",
"events" : [ {
"introduced" : "1.0.0-rc.0"
}, {
"last_affected" : "2.5.0"
} ]
} ]
} ],
"references" : [ {
"type" : "WEB",
"url" : "https://github.com/prometheus/prometheus/security/advisories/GHSA-8rm2-7qqf-34qm"
}, {
"type" : "ADVISORY",
"url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-42154"
}, {
"type" : "WEB",
"url" : "https://github.com/prometheus/prometheus/pull/18584"
}, {
"type" : "WEB",
"url" : "https://github.com/prometheus/prometheus/pull/18585"
}, {
"type" : "PACKAGE",
"url" : "https://github.com/prometheus/prometheus"
}, {
"type" : "WEB",
"url" : "https://github.com/prometheus/prometheus/releases/tag/v3.11.3"
}, {
"type" : "WEB",
"url" : "https://github.com/prometheus/prometheus/releases/tag/v3.5.3"
} ],
"database_specific" : {
"cwe_ids" : [ "CWE-400", "CWE-789" ],
"severity" : "HIGH",
"github_reviewed" : true,
"github_reviewed_at" : "2026-05-05T19:34:05Z",
"nvd_published_at" : "2026-05-04T19:16:04Z"
}
}