CVE-2024-1023 is a medium-severity (CVSS 6.5) CWE-401 vulnerability in io.vertx:vertx-core. A fix is available for io.vertx:vertx-core — see the affected versions and patch details below.
Io.vertx/vertx-core: memory leak due to the use of netty fastthreadlocal data structures in vertx
Exploitation Status
Proof-of-concept exploit code exists
- CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
Exploitation and automatability from CISA’s SSVC triage for CVE-2024-1023.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
Where this sits among everything scored
Real-World Exposure
io.vertx:vertx-core☕io.vertx:vertx-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
A vulnerability in the Eclipse Vert.x toolkit results in a memory leak due to using Netty FastThreadLocal data structures. Specifically, when the Vert.x HTTP client establishes connections to different hosts, triggering the memory leak. The leak can be accelerated with intimate runtime knowledge, allowing an attacker to exploit this vulnerability. For instance, a server accepting arbitrary internet addresses could serve as an attack vector by connecting to these addresses, thereby accelerating the memory leak.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| ☕Maven | io.vertx:vertx-core | ≥ 4.5.0&&< 4.5.2 | 4.5.2io.vertx:vertx-core:4.5.2 |
| ☕Maven | io.vertx:vertx-core | ≥ 4.4.5&&< 4.4.7 | 4.4.7io.vertx:vertx-core:4.4.7 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for io.vertx:vertx-core, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update io.vertx:vertx-core to 4.5.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2024-1023 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
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.
Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.Source: Red Hat security advisory for CVE-2024-1023 (CC BY 4.0)
| Product | Fixed in | Advisory |
|---|---|---|
| CEQ 3.2 | vert.x | RHSA-2024:1706 |
| Cryostat 2 on RHEL 8 | cryostat-tech-preview/cryostat-grafana-dashboard-rhel8:2.4.0-7 | RHSA-2024:2088 |
| MTA-6.2-RHEL-9 | mta/mta-windup-addon-rhel9:6.2.3-2 | RHSA-2024:3989 |
| Red Hat AMQ Streams 2.7.0 | vert.x | RHSA-2024:3527 |
| Red Hat build of Apache Camel 4.4.1 for Spring Boot 3.2 | vert.x | RHSA-2024:4884 |
| Red Hat build of Quarkus 3.2.11.Final | io.vertx/vertx-core:4.4.8.redhat-00001 | RHSA-2024:1662 |
| RHINT Service Registry 2.5.11 GA | vert.x | RHSA-2024:2833 |
Frequently Asked Questions
Is CVE-2024-1023 in your dependencies?
Find it across Maven, including transitive dependencies.