CVE-2026-73564 frp: Unauthenticated Remote Denial of Service in the frp SSH Tunnel Gateway via Integer Overflow

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 bound...

CVE-2026-73564 frp: Unauthenticated Remote Denial of Service in the frp SSH Tunnel Gateway via Integer Overflow

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 bound...

CVE-2026-73564

The CVE affects frp (frps) with the SSH Tunnel Gateway enabled. A root cause was an integer overflow in parsing an SSH exec channel: the code adds 4 to an attacker-controlled 4-byte length, and 0xFFFFFFFF wraps to 3, causing a bounds check bypass and a panic in TunnelServer.handleNewChannel. When...