CVE-2023-39321: Golang Go

High severity, CVSS 7.5. EPSS: 1.3% chance of exploitation in the next 30 days.

Processing an incomplete post-handshake message for a QUIC connection can cause a panic.

Affected products

• Golang Go: from 1.21.0, before 1.21.1 (fixed in 1.21.1)

Published 2023-09-08. Last modified 2026-06-17.