# CVE-2024-1635: Undertow: out-of-memory error after several closed connections with wildfly-http-client protocol > An attacker can exhaust server memory and file limits by rapidly opening and closing connections, causing a denial of service in Undertow. - **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`) - **Exploited in the wild:** Not known - **Login needed:** Not needed - **Attackable:** Over the internet - **Victim action needed:** Not needed - **Fix available:** Yes - **Published:** 19 Feb 2024 - **Updated:** 7 Oct 2026 - **Also known as:** CLSA-2026-1781139194, DEBIAN-CVE-2024-1635, GHSA-w6qf-42m7-vh68, UBUNTU-CVE-2024-1635 ## What is CVE-2024-1635? CVE-2024-1635 is a high-severity denial of service vulnerability in Netapp Active Iq Unified Manager, published on 19 Feb 2024. An attacker can exploit it over the internet without logging in, with no action from the victim. ### Official 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. Weakness: CWE-400 (Uncontrolled Resource Consumption) ## Which versions are affected by CVE-2024-1635? 4 open source packages ship an affected version, including io.undertow:undertow-core. It affects 9 products. | Package | Ecosystem | Affected | Fixed in | | --- | --- | --- | --- | | `io.undertow:undertow-core` | Maven | All versions | 2.2.31.Final | | `io.undertow:undertow-core` | Maven | All versions | 2.2.31.Final | | `io.undertow:undertow-core` | Maven | From 2.3.0.Final | 2.3.12.Final | | `io.undertow:undertow-core` | Maven | From 2.3.0.Final | 2.3.12.Final | Products: Netapp Active Iq Unified Manager, Netapp Oncommand Workflow Automation, Redhat Fuse, Redhat Integration Camel for Spring Boot, Redhat Jboss Enterprise Application Platform, Redhat Openshift Container Platform, Redhat Openshift Container Platform for Linuxone, Redhat Openshift Container Platform for Power, Redhat Single Sign-On. ## How do I fix CVE-2024-1635? Upgrade io.undertow:undertow-core to a fixed version for your release line: 2.2.31.Final or 2.3.12.Final. ## Is CVE-2024-1635 being exploited? There is no known exploitation of CVE-2024-1635 in the wild and no public exploit code. ## Other vulnerabilities in Netapp Active Iq Unified Manager - [CVE-2022-31692](https://insights.sbomify.com/CVE-2022-31692/): Spring Security authorization rules can be bypassed via forward or include dispatcher types (critical 9.8) - [CVE-2022-2526](https://insights.sbomify.com/CVE-2022-2526/): Use after free in systemd-resolved (critical 9.8) - [CVE-2022-22978](https://insights.sbomify.com/CVE-2022-22978/): Authorization bypass in Spring Security (critical 9.8) - [CVE-2021-22931](https://insights.sbomify.com/CVE-2021-22931/): Code injection in Node (critical 9.8) - [CVE-2018-2938](https://insights.sbomify.com/CVE-2018-2938/): Code injection in Java (critical 9.0) ## Fix prompt for AI coding agents ```text Check this codebase for CVE-2024-1635 and fix it if it is affected. What it is: CVE-2024-1635 is a high-severity denial of service vulnerability in Netapp Active Iq Unified Manager, published on 19 Feb 2024. An attacker can exploit it over the internet without logging in, with no action from the victim. Exploitation: There is no known exploitation of CVE-2024-1635 in the wild and no public exploit code. Affected packages and fixed versions: - io.undertow:undertow-core (Maven): affected all versions; fixed in 2.2.31.Final - io.undertow:undertow-core (Maven): affected all versions; fixed in 2.2.31.Final - io.undertow:undertow-core (Maven): affected from 2.3.0.Final; fixed in 2.3.12.Final - io.undertow:undertow-core (Maven): affected from 2.3.0.Final; fixed in 2.3.12.Final Task: 1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies. 2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it. 3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead. 4. Run the tests and summarise what changed and why. 5. If nothing in the project is affected, say so and change nothing. Reference: https://insights.sbomify.com/CVE-2024-1635/ (Markdown: https://insights.sbomify.com/CVE-2024-1635/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2024-1635 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2024-1635 - OSV: https://osv.dev/vulnerability/CVE-2024-1635 --- From sbomify Insights: https://insights.sbomify.com/CVE-2024-1635/ Summaries are generated and may contain mistakes; the official description above is the record.