CVE-2026-40983 — micrometer-core
HIGHCVE-2026-40983 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 gRPC server instrumentation DoS
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-2026-40983.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
CVE-2026-40983 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 379,842 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
io.micrometer:micrometer-core☕io.micrometer:micrometer-coreReal-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 gRPC requests that may cause a denial-of-service (DoS) condition.
Affected versions: Micrometer 1.16.0 through 1.16.5; 1.15.0 through 1.15.11.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| ☕Maven | io.micrometer:micrometer-core | ≥ 1.16.0&&< 1.16.6 | 1.16.6io.micrometer:micrometer-core:1.16.6 |
| ☕Maven | io.micrometer:micrometer-core | ≥ 1.15.0&&< 1.15.12 | 1.15.12io.micrometer:micrometer-core:1.15.12 |
Detection & mitigation playbook
Open-source dependencyDetect
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.
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-2026-40983 is resolved across your whole dependency graph.
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.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2026-40983 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2026-40983. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
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.
This is an Important denial-of-service vulnerability in Micrometer, as a remote unauthenticated attacker can disrupt the availability of affected systems by sending specially crafted gRPC requests. The broad accessibility of gRPC endpoints in typical deployments contributes to the elevated risk, allowing for…
To mitigate this issue, restrict network access to services exposing Micrometer's gRPC endpoints to trusted clients only. Implement firewall rules to limit inbound connections to the specific ports used by gRPC. If gRPC functionality is not essential for the deployment, consider disabling it entirely to eliminate the attack vector. Any changes to network configurations or service settings may require a service restart to take effect, potentially impacting availability during the transition.Source: Red Hat security advisory for CVE-2026-40983 (CC BY 4.0)
| Product | Fixed in | Advisory |
|---|---|---|
| AMQ Clients 2026.Q3 | micrometer-core | RHSA-2026:69459 |
| Red Hat AMQ Broker 7.14.1 | micrometer-core | RHSA-2026:66488 |
| Red Hat build of Keycloak 26.6 | rhbk/keycloak-operator-bundle:26.6.5-1 | RHSA-2026:50849 |
| Red Hat build of Keycloak 26.6.5 | micrometer-core | RHSA-2026:50848 |
| Red Hat Data Grid 8.6.2 | micrometer-core | RHSA-2026:41951 |
| Streams for Apache Kafka 3.2.1 | micrometer-core | RHSA-2026:54435 |
| Red Hat OpenShift Dev Spaces 3.30 | devspaces/openvsx-rhel9:1787759145 | RHSA-2026:62260 |
Frequently Asked Questions
Is CVE-2026-40983 in your dependencies?
O3 Security finds CVE-2026-40983 across Maven dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.