CVE-2026-31814
HIGH7.5EPSS 0.03%Yamux vulnerable to remote Panic via malformed WindowUpdate credit
Description
### 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
Affected packages (2)
- crates.io/yamux>= 0.13.0, < 0.13.9
- Debian/rust-yamuxfrom 0
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 4.0 | — | 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 |
| osv | CVSS 3.1 | HIGH7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
References (7)
- ADVISORYhttps://nvd.nist.gov/vuln/detail/CVE-2026-31814
- ADVISORYhttps://security-tracker.debian.org/tracker/CVE-2026-31814
- PATCHhttps://github.com/libp2p/rust-yamux
- WEBhttps://github.com/libp2p/rust-yamux/commit/b1aae09d60c0bd6a5915a5448f4e8cbc5174db53
- WEBhttps://github.com/libp2p/rust-yamux/pull/221
- WEBhttps://github.com/libp2p/rust-yamux/releases/tag/yamux-v0.13.9
- WEBhttps://github.com/libp2p/rust-yamux/security/advisories/GHSA-4w32-2493-32g7