Rust SSH Client/Server Library Vulnerability in Russh

CVE-2026-102822

What is CVE-2026-102822?

Russh, a Rust-based SSH client and server library, allows an attacker to exploit a flaw in the MAC handling mechanism prior to version 0.63.1. When a connection permits mac=none, it incorrectly negotiates with block ciphers that require a MAC. This results in a scenario where a remote peer can trigger a panic by sending a packet with a decrypted length of zero, leading the library to attempt to access a part of the buffer incorrectly, ultimately terminating the connection task. The vulnerability has been addressed in version 0.63.1.

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