Resource exhaustion in Netty
CVE-2023-34462
Netty is an asynchronous event-driven network application framework for rapid development of maintainable high performance protocol servers & clients. The `SniHandler` can allocate up to 16MB of heap for each channel during the TLS handshake. When the handler or the channel does not have an idle timeout, it can be used to make a TCP server using the `SniHandler` to allocate 16MB of heap. The `SniHandler` class is a handler that waits for the TLS handshake to configure a `SslHandler` according to the indicated server name by the `ClientHello` record. For this matter it allocates a `ByteBuf` using the value defined in the `ClientHello` record. Normally the value of the packet should be smaller than the handshake packet but there are not checks done here and the way the code is written, it is possible to craft a packet that makes the `SslClientHelloHandler`. This vulnerability has been fixed in version 4.1.94.Final.
Vulnerability class: DoS (Denial of Service)
EPSS: 0.025 (82.8th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H.
Affected products
- Netty — versions < 4.1.94.Final
Weakness classification (CWE)
Public proof-of-concept exploits
References
- security-advisories@github.com (x_refsource_CONFIRM, Exploit, Vendor Advisory)
- security-advisories@github.com (Patch, x_refsource_MISC)
- security-advisories@github.com
- security-advisories@github.com
- security-advisories@github.com
Frequently asked questions
- What is CVE-2023-34462?
- CVE-2023-34462 is a medium-severity vulnerability in Netty, classified under Uncontrolled Resource Consumption. CVSS score: 6.5/10. Published 2023-06-22.
- How severe is CVE-2023-34462?
- Medium severity. CVSS v3 base score is 6.5 out of 10.
- Is CVE-2023-34462 known to be exploited?
- 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.