CVE-2022-21698 | Uncontrolled Resource Consumption in promhttp

client_golang is the instrumentation library for Go applications in Prometheus, and the promhttp package in client_golang provides tooling around HTTP servers and clients. In client_golang prior to version 1.11.1, HTTP server is susceptible to a Denial of Service through unbounded cardinality, and potential memory exhaustion, when handling requests with non-standard HTTP methods. In order to be affected, an instrumented software must use any of `promhttp.InstrumentHandler*` middleware except `RequestsInFlight`; not filter any specific methods (e.g GET) before middleware; pass metric with `method` label name to our middleware; and not have any firewall/LB/proxy that filters away requests with unknown `method`. client_golang version 1.11.1 contains a patch for this issue. Several workarounds are available, including removing the `method` label name from counter/gauge used in the InstrumentHandler; turning off affected promhttp handlers; adding custom middleware before promhttp handler that will sanitize the request method given by Go http.Request; and using a reverse proxy or web application firewall, configured to only allow a limited set of methods.

Published: 2022-02-15 Last update: 2024-11-21 Assigner: [email protected] Source: [email protected]

Conclusion & alert: CVE-2022-21698 is rated Moderate Risk (52.5/100): CVSS High severity, with medium exploitation likelihood (EPSS 0.45%). Mandatory action: Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2022-21698

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-05-16 0.28% 0.45% +0.17%
2 2026-05-09 0.24% 0.28% +0.05%
3 2026-05-05 0.24%

Full EPSS history (25 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2022-21698

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.5 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
3.9 3.6 [email protected]
7.5 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
3.9 3.6 [email protected]
5.0 2.0 MEDIUM
AV:N/AC:L/Au:N/C:N/I:N/A:P Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:N)
No confidentiality impact.
Integrity impact (I:N)
No integrity impact.
Availability impact (A:P)
Partial availability impact.
10.0 2.9 [email protected]

Weakness enumeration for CVE-2022-21698

GitHub Security Advisory for CVE-2022-21698

GHSA-cg3q-j54f-5p7p · Severity: high · Ecosystem: go — Uncontrolled Resource Consumption in promhttp

OS Trackers for CVE-2022-21698

vendor priority summary link
debian not yet assigned CVE-2022-21698 not yet assigned priority: Debian including 1 source packages (golang-github-prometheus-client-golang), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 4, open 1. https://security-tracker.debian.org/tracker/CVE-2022-21698
redhat medium https://access.redhat.com/security/cve/CVE-2022-21698
suse high https://www.suse.com/security/cve/CVE-2022-21698/
ubuntu medium CVE-2022-21698 medium priority: Ubuntu including 1 source packages (golang-github-prometheus-client-golang), 14 status rows across 14 suites (bionic, focal, impish, jammy, kinetic, lunar, mantic, noble, oracular, plucky, questing, trusty, upstream, xenial): ignored 8, needs-triage 6. https://ubuntu.com/security/CVE-2022-21698

Affected software / configurations for CVE-2022-21698

Vendor Product Version Raw CPE
prometheus client_golang < 1.11.1 cpe:2.3:a:prometheus:client_golang:*:*:*:*:*:go:*:*
fedoraproject fedora 34 cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:*
fedoraproject fedora 35 cpe:2.3:o:fedoraproject:fedora:35:*:*:*:*:*:*:*
fedoraproject fedora 36 cpe:2.3:o:fedoraproject:fedora:36:*:*:*:*:*:*:*
fedoraproject extra_packages_for_enterprise_linux 7.0 cpe:2.3:a:fedoraproject:extra_packages_for_enterprise_linux:7.0:*:*:*:*:*:*:*
fedoraproject extra_packages_for_enterprise_linux 8.0 cpe:2.3:a:fedoraproject:extra_packages_for_enterprise_linux:8.0:*:*:*:*:*:*:*
rdo_project rdo cpe:2.3:a:rdo_project:rdo:-:*:*:*:*:*:*:*
fedoraproject fedora 37 cpe:2.3:o:fedoraproject:fedora:37:*:*:*:*:*:*:*

References for CVE-2022-21698

URL Tags
https://github.com/prometheus/client_golang/pull/962 Patch Third Party Advisory
https://github.com/prometheus/client_golang/pull/987 Patch Third Party Advisory
https://github.com/prometheus/client_golang/releases/tag/v1.11.1 Release Notes Third Party Advisory
https://github.com/prometheus/client_golang/security/advisories/GHSA-cg3q-j54f-5p7p Issue Tracking Third Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/2IK53GWZ475OQ6ENABKMJMTOBZG6LXUR/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/2PFW6Q2LXXWTFRTMTRN4ZGADFRQPKJ3D/
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