CVE-2024-1635 is a high-severity (CVSS 7.5) Uncontrolled Resource Consumption vulnerability in io.undertow:undertow-core. A fix is available for io.undertow:undertow-core — see the affected versions and patch details below.
Undertow Uncontrolled Resource Consumption Vulnerability
Exploitation Status
No confirmed exploitation observed yet
- 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-2024-1635.
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-2024-1635 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 377,333 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.undertow:undertow-core☕io.undertow:undertow-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 was found in Undertow. This vulnerability impacts a server that supports the wildfly-http-client protocol. Whenever a malicious user opens and closes a connection with the HTTP port of the server and then closes the connection immediately, the server will end with both memory and open file limits exhausted at some point, depending on the amount of memory available.
At HTTP upgrade to remoting, the WriteTimeoutStreamSinkConduit leaks connections if RemotingConnection is closed by Remoting ServerConnectionOpenListener. Because the remoting connection originates in Undertow as part of the HTTP upgrade, there is an external layer to the remoting connection. This connection is unaware of the outermost layer when closing the connection during the connection opening procedure. Hence, the Undertow WriteTimeoutStreamSinkConduit is not notified of the closed connection in this scenario. Because WriteTimeoutStreamSinkConduit creates a timeout task, the whole dependency tree leaks via that task, which is added to XNIO WorkerThread. So, the workerThread points to the Undertow conduit, which contains the connections and causes the leak.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| ☕Maven | io.undertow:undertow-core | ≥ 2.3.0.Final&&< 2.3.12.Final | 2.3.12.Finalio.undertow:undertow-core:2.3.12.Final |
| ☕Maven | io.undertow:undertow-core | all versions | 2.2.31.Finalio.undertow:undertow-core:2.2.31.Final |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for io.undertow:undertow-core, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update io.undertow:undertow-core to 2.3.12.Final or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2024-1635 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.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2024-1635 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2024-1635. 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 rated as Important due to the fact that this might be an unauthenticated remote issue exploited by a malicious user, causing a denial of service (DoS) to the affected server.
| Product | Fixed in | Advisory |
|---|---|---|
| Red Hat build of Apache Camel 4.4.1 for Spring Boot 3.2 | see advisory | RHSA-2024:4884 |
| Red Hat Fuse 7.13.0 | see advisory | RHSA-2024:3354 |
| Red Hat JBoss Enterprise Application Platform | io.undertow/undertow-core:2.2.30.SP1-redhat-00001 | RHSA-2024:1677 |
| Red Hat JBoss Enterprise Application Platform 7.1 EUS for RHEL 7 | eap7-activemq-artemis-0:1.5.5.016-1.redhat_00001.1.ep7.el7 | RHSA-2025:4226 |
| Red Hat JBoss Enterprise Application Platform 7.3 EUS for RHEL 7 | eap7-jackson-annotations-0:2.10.4-3.redhat_00006.1.el7eap | RHSA-2025:9583 |
| Red Hat JBoss Enterprise Application Platform 7.4 for RHEL 8 | eap7-undertow-0:2.2.30-1.SP1_redhat_00001.1.el8eap | RHSA-2024:1675 |
| Red Hat JBoss Enterprise Application Platform 7.4 for RHEL 9 | eap7-undertow-0:2.2.30-1.SP1_redhat_00001.1.el9eap | RHSA-2024:1676 |
| Red Hat JBoss Enterprise Application Platform 7.4 on RHEL 7 | eap7-undertow-0:2.2.30-1.SP1_redhat_00001.1.el7eap | RHSA-2024:1674 |
Frequently Asked Questions
Is CVE-2024-1635 in your dependencies?
O3 Security finds CVE-2024-1635 across Maven dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.