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HIGH severity

CVE-2026-40984 — micrometer-core

HIGHFix: micrometer-metrics/micrometer@36da131

CVE-2026-40984 is a high-severity (CVSS 7.5) Uncontrolled Resource Consumption vulnerability in io.micrometer:micrometer-core. A fix is available for io.micrometer:micrometer-core — see the affected versions and patch details below.

Micrometer HTTP server instrumentations DoS

Published
Jun 9, 2026
Updated
Sep 11, 2026
Affected
13 pkgs
Patched
6 / 13
Exploits
None indexed
Exploitation data as of Sep 26, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

  • CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
  • CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2026-40984.

EPSS Exploitation Probability

via FIRST.org ↗
1.1%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs63th percentile — riskier than 63% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

CVE-2026-40984 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.

Where this sits among everything scored

Of 379,842 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.

Real-World Exposure

13 pkgs affected
☕io.micrometer:micrometer-core☕io.micrometer:micrometer-core☕io.micrometer:micrometer-core☕io.micrometer:micrometer-core☕io.micrometer:micrometer-core☕io.micrometer:micrometer-jetty12☕io.micrometer:micrometer-jetty12☕io.micrometer:micrometer-jetty12+5 more

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Maven packages — download data is not available via public APIs for these ecosystems.

Description

In Micrometer, it is possible for a user to provide specially crafted HTTP requests that may cause a denial-of-service (DoS) condition.

Affected versions: micrometer-core 1.16.0 through 1.16.5; 1.15.0 through 1.15.11; 1.14.0 through 1.14.15; 1.13.0 through 1.13.18; 1.9.0 through 1.9.17. micrometer-jetty11 1.16.0 through 1.16.5; 1.15.0 through 1.15.11; 1.14.0 through 1.14.15; 1.13.0 through 1.13.18. micrometer-jetty12 1.16.0 through 1.16.5; 1.15.0 through 1.15.11; 1.14.0 through 1.14.15; 1.13.0 through 1.13.18.

Affected Packages

13 total 6 fixed
EcosystemPackageVulnerable rangeFix
☕Mavenio.micrometer:micrometer-core≥ 1.16.0&&< 1.16.61.16.6io.micrometer:micrometer-core:1.16.6
☕Mavenio.micrometer:micrometer-core≥ 1.15.0&&< 1.15.121.15.12io.micrometer:micrometer-core:1.15.12
☕Mavenio.micrometer:micrometer-core≥ 1.14.0No fix
☕Mavenio.micrometer:micrometer-core≥ 1.10.0No fix
☕Mavenio.micrometer:micrometer-coreall versionsNo fix
☕Mavenio.micrometer:micrometer-jetty12≥ 1.16.0&&< 1.16.61.16.6io.micrometer:micrometer-jetty12:1.16.6

Detection & mitigation playbook

Open-source dependency

  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for io.micrometer:micrometer-core, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

  2. Fix

    Update io.micrometer:micrometer-core to 1.16.6 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-40984 is resolved across your whole dependency graph.

  3. Workarounds

    Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.

Fixing This On Your OS

If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.

Red HatImportant

This is an Important denial-of-service vulnerability in Micrometer, a component present in several Red Hat products. A remote, unauthenticated attacker can exploit this flaw by sending specially crafted HTTP requests, leading to resource exhaustion and disrupting the availability of affected services. Exploitation of…

ProductFixed inAdvisory
AMQ Clients 2026.Q3micrometer-coreRHSA-2026:69459
Red Hat AMQ Broker 7.13.6micrometer-coreRHSA-2026:66545
Red Hat AMQ Broker 7.14.1micrometer-coreRHSA-2026:66488
Red Hat build of Apache Camel 4.18.1.P1 for Spring Boot 3.5.16micrometer-coreRHSA-2026:37390
Red Hat build of Keycloak 26.6rhbk/keycloak-operator-bundle:26.6.5-1RHSA-2026:50849
Red Hat build of Keycloak 26.6.5micrometer-coreRHSA-2026:50848
Red Hat Data Grid 8.6.2micrometer-coreRHSA-2026:41951
Streams for Apache Kafka 3.2.1micrometer-coreRHSA-2026:54435

Frequently Asked Questions

In Micrometer, it is possible for a user to provide specially crafted HTTP requests that may cause a denial-of-service (DoS) condition. Affected versions: micrometer-core 1.16.0 through 1.16.5; 1.15.0 through 1.15.11; 1.14.0 through 1.14.15; 1.13.0 through 1.13.18; 1.9.0 through 1.9.17. micrometer-jetty11 1.16.0 through 1.16.5; 1.15.0 through 1.15.11; 1.14.0 through 1.14.15; 1.13.0 through 1.13.18. micrometer-jetty12 1.16.0 through 1.16.5; 1.15.0 through 1.15.11; 1.14.0 through 1.14.15; 1.13.0 through 1.13.18.
O3 Security · Impact-Aware SCA

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CVE-2026-40984: micrometer DoS (High 7.5) | O3 Security