EUVD-2026-12083
GHSA-4w32-2493-32g7
CVSS Vector
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
Lifecycle Timeline
4Description
### 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
Analysis
Integer overflow in Rust's Yamux implementation allows unauthenticated remote attackers to crash target nodes by sending specially crafted WindowUpdate frames that trigger arithmetic overflow in stream send-window accounting. An attacker can establish a Yamux session and transmit malicious frames without authentication, causing a panic in the connection state machine and resulting in denial of service. …
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Remediation
Within 24 hours: Identify all systems and applications using the Rust Yamux library and assess exposure in production environments. Within 7 days: Apply available vendor patches to all affected systems and validate in non-production environments first. …
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