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HIGH

GHSA-4w32-2493-32g7

Yamux vulnerable to remote Panic via malformed WindowUpdate credit

Details

### Sumary The Rust implementation of Yamux accepts `WindowUpdate` credit values from the remote peer and applies them to per-stream send-window state. A specially crafted `WindowUpdate` can cause arithmetic overflow in send-window accounting, which triggers a panic in the connection state machine. This is remotely reachable over a normal network connection and does not require authentication. #### Attack Scenario An attacker that can establish a Yamux session with a target node can crash the target by sending two validly encoded Yamux frames: 1. Open a stream (e.g. DATA + SYN) so the stream exists with initial send-window state (`DEFAULT_CREDIT`). 2. Send a WindowUpdate on that stream with a very large credit value (e.g. 0xFFFF_0000) such that adding credit to the current send-window overflows u32. ### Impact Remote unauthenticated denial of service. An attacker can repeatedly trigger panics by reconnecting and replaying the crafted frame sequence. ### Patches Users should upgrade to `yamux` `v0.13.9`

This vulnerability was originally submitted by @revofusion to the Ethereum Foundation bug bounty program

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Affected packages

crates.io/yamux
Introduced in: 0.13.0Fixed in: 0.13.9

Upgrade yamux to 0.13.9 or newer (ecosystem crates.io).

References