CVE-2026-73564: Fatedier Frp

High severity, CVSS 8.7. EPSS: 0.5% chance of exploitation in the next 30 days.

frp is a fast reverse proxy. From 0.53.0 until 0.70.1, frp's optional SSH Tunnel Gateway in pkg/ssh/server.go parses an SSH exec channel request by adding 4 to an attacker-controlled four-byte big-endian length. A length of 0xFFFFFFFF makes the uint32 addition wrap to 3, defeats the payload bounds check, and causes payload[4:3] to panic in TunnelServer.handleNewChannel. When no authorized-keys file is configured, sshConfig.NoClientAuth permits an unauthenticated peer to reach this channel phase before the frp token is checked, so a single five-byte request terminates the frps process and drops every active tunnel. This issue is fixed in version 0.70.1.

Affected products

• Fatedier Frp: from 0.53.0, before 0.70.1 (fixed in 0.70.1)

Published 2026-08-13. Last modified 2026-09-18.