CVE-2026-31814: libp2p rust-yamux Integer Overflow or Wraparound

Vulnerability summary

CVE-2026-31814 is a high (CVSS 8.7) Integer Overflow or Wraparound vulnerability in libp2p rust-yamux. EPSS estimates a 0.60% chance of exploitation in the next 30 days, higher than 47.4% of scored vulnerabilities. 1 public exploit is recorded.

Timeline

1. 13-03-2026
   PublishedVulnerability first disclosed.
2. 13-03-2026
   Last modifiedVulnerability information updated.

Description

Yamux is a stream multiplexer over reliable, ordered connections such as TCP/IP. From 0.13.0 to before 0.13.9, 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. This vulnerability is fixed in 0.13.9.

• CWE-190Integer Overflow or WraparoundThe product performs a calculation that can produce an integer overflow or wraparound when the logic assumes that the resulting value will always be larger than the original value. This occurs when an integer value is incremented to a value that is too large to store in the associated representation. When this occurs, the value may become a very small or negative number.