CVE-2026-32314: Yamux remote Panic via malformed Data frame with SYN set and len = 262145
Summary The Rust implementation of Yamux can panic when processing a crafted inbound Data frame that sets SYN and uses a body length greater than DEFAULTCREDIT (e.g. 262145). On the first packet of a new inbound stream, stream state is created and a receiver is queued before oversized-body validation completes. When validation fails, the temporary stream is dropped and cleanup may call remove(...).expect("stream not found"), triggering a panic in the connection state machine. This is remotely reachable over a normal Yamux session and does not require authentication. kind of vulnerability is it? Who is Attack Scenario An attacker that can establish a Yamux session with a target node can crash the target by sending a single validly encoded Yamux Data|SYN frame with an oversized body: 1. Establish a standard authenticated transport session that negotiates Yamux. 2. Send one Yamux frame with: - Tag = Data - Flags = SYN - StreamId = 1 (or any new inbound stream id) - Length = DEFAULTCREDIT + 1 (e.g. 262145) - Body of matching size This can trigger a panic (stream not found) and terminate the process, depending on host application panic policy. Patches Users should upgrade to yamux v0.13.10
This vulnerability was originally submitted by @revofusion to the Ethereum Foundation bug bounty program
Other sources
Yamux is a stream multiplexer over reliable, ordered connections such as TCP/IP. Prior to 0.13.10, the Rust implementation of Yamux can panic when processing a crafted inbound Data frame that sets SYN and uses a body length greater than DEFAULTCREDIT (e.g. 262145). On the first packet of a new inbound stream, stream state is created and a receiver is queued before oversized-body validation completes. When validation fails, the temporary stream is dropped and cleanup may call remove(...).expect("stream not found"), triggering a panic in the connection state machine. This is remotely reachable over a normal Yamux session and does not require authentication. This vulnerability is fixed in 0.13.10.
— MITRE
Affected Software
Event History
Frequently Asked Questions
What is the severity of CVE-2026-32314?
CVE-2026-32314 has been classified as a high severity vulnerability due to the potential for a panic caused by a malformed Data frame.
How do I fix CVE-2026-32314?
To fix CVE-2026-32314, update the Yamux implementation to version 0.13.10 or later.
What software is affected by CVE-2026-32314?
CVE-2026-32314 affects the Rust implementation of Yamux versions prior to 0.13.10.
What type of attack does CVE-2026-32314 represent?
CVE-2026-32314 represents a denial of service vulnerability due to a panic triggered by crafted input.
Is there a known exploit for CVE-2026-32314?
As of now, there is no publicly known exploit for CVE-2026-32314, but the vulnerability can lead to application crashes.