CVE-2024-5971 Undertow: response write hangs in case of java 17 tlsv1.3 newsessionticket
Undertow fails to terminate chunked responses in Java 17 TLSv1.3, causing clients to hang and leading to server-side resource exhaustion and denial of service.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2024-5971?
CVE-2024-5971 is a high-severity denial of service vulnerability in Red Hat Build of Keycloak, published on 8 Jul 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, where the chunked response hangs after the body was flushed. The response headers and body were sent but the client would continue waiting as Undertow does not send the expected 0\r\n termination of the chunked response. This results in uncontrolled resource consumption, leaving the server side to a denial of service attack. This happens only with Java 17 TLSv1.3 scenarios.
Weakness: CWE-674
Which versions are affected by CVE-2024-5971?
4 open source packages ship an affected version, including io.undertow:undertow-core.
| Package | Affected | Fixed in |
|---|---|---|
io.undertow:undertow-core Maven | All versions | 2.2.34.Final |
io.undertow:undertow-core Maven | All versions | 2.2.34.Final |
io.undertow:undertow-core Maven | From 2.3.0.Alpha1 | 2.3.15.Final |
io.undertow:undertow-core Maven | From 2.3.0.Alpha1 | 2.3.15.Final |
How do I fix CVE-2024-5971?
Upgrade io.undertow:undertow-core to a fixed version for your release line: 2.2.34.Final or 2.3.15.Final.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2024-5971 being exploited?
There is no known exploitation of CVE-2024-5971 in the wild and no public exploit code.
Sources
Also known as CLSA-2026-1775435425, DEBIAN-CVE-2024-5971, GHSA-xpp6-8r3j-ww43, UBUNTU-CVE-2024-5971.