Summary
Yamux vulnerable to remote Panic via malformed Data frame with SYN set and len = 262145
The Rust implementation of Yamux can panic when processing a crafted inbound Data frame that sets SYN and uses a body length greater than DEFAULT_CREDIT (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:
- Establish a standard authenticated transport session that negotiates Yamux.
- Send one Yamux frame with:
- Tag = Data
- Flags = SYN
- StreamId = 1 (or any new inbound stream id)
- Length = DEFAULT_CREDIT + 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.
Impact
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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Users should upgrade to yamux v0.13.10
This vulnerability was originally submitted by @revofusion to the Ethereum Foundation bug bounty program
Frequently Asked Questions
- What is CVE-2026-32314? CVE-2026-32314 is a high-severity security vulnerability in yamux (rust), affecting versions < 0.13.10. It is fixed in 0.13.10.
- Which versions of yamux are affected by CVE-2026-32314? yamux (rust) versions < 0.13.10 is affected.
- Is there a fix for CVE-2026-32314? Yes. CVE-2026-32314 is fixed in 0.13.10. Upgrade to this version or later.
- Is CVE-2026-32314 exploitable, and should I be worried? Whether CVE-2026-32314 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2026-32314 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2026-32314? Upgrade
yamuxto 0.13.10 or later.