CVE-2024-32984 Yamux Memory Exhaustion Vulnerability via Active::pending_frames property
Remote attackers can exhaust memory in applications using the Rust Yamux library by blocking TCP transmission, causing process termination.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2024-32984?
CVE-2024-32984 is a high-severity denial of service vulnerability in libp2p rust-yamux, published on 1 May 2024. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
Yamux is a stream multiplexer over reliable, ordered connections such as TCP/IP. The Rust implementation of the Yamux stream multiplexer uses a vector for pending frames. This vector is not bounded in length. Every time the Yamux protocol requires sending of a new frame, this frame gets appended to this vector. This can be remotely triggered in a number of ways, for example by: 1. Opening a new libp2p Identify stream. This causes the node to send its Identify message. Of course, every other protocol that causes the sending of data also works. The larger the response, the more data is enqueued. 2. Sending a Yamux Ping frame. This causes a Pong frame to be enqueued. Under normal circumstances, this queue of pending frames would be drained once they’re sent out over the network. However, the attacker can use TCP’s receive window mechanism to prevent the victim from sending out any data: By not reading from the TCP connection, the receive window will never be increased, and the victim won’t be able to send out any new data (this is how TCP implements backpressure). Once this happens, Yamux’s queue of pending frames will start growing indefinitely. The queue will only be drained once the underlying TCP connection is closed. An attacker can cause a remote node to run out of memory, which will result in the corresponding process getting terminated by the operating system.
Weakness: CWE-400
Which versions are affected by CVE-2024-32984?
2 open source packages ship an affected version, including yamux.
| Package | Affected | Fixed in |
|---|---|---|
yamux crates.io | From 0.13.0 | 0.13.2 |
yamux crates.io | From 0.13.0 | 0.13.2 |
How do I fix CVE-2024-32984?
Upgrade yamux to 0.13.2 or later.
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-2024-32984 being exploited?
There is no known exploitation of CVE-2024-32984 in the wild and no public exploit code.
Sources
Also known as GHSA-3999-5ffv-wp2r.