CVE-2026-73489 Russh: Post-auth remote panic via pty-req with more than 130 terminal-mode records
An authenticated attacker can crash the SSH server by sending a pty-req with excessive terminal-mode records, causing a panic.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-73489?
CVE-2026-73489 is a medium-severity denial of service vulnerability in Eugeny russh, published on 13 Aug 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
Russh is a Rust SSH client & server library. Prior to 0.62.4, an authenticated SSH client can cause a denial of service by sending a pty-req channel request with more than 130 terminal-mode records. The parser in russh/src/server/encrypted.rs stores terminal modes in a fixed 130-entry [(Pty::TTY_OP_END, 0); 130] array but continues increasing the mode count, then constructs an out-of-bounds slice and panics before the application pty_request handler runs. The panic terminates the server session task without causing memory corruption. This issue is fixed in version 0.62.4.
Weakness: CWE-129
Which versions are affected by CVE-2026-73489?
2 open source packages ship an affected version, including russh.
| Package | Affected | Fixed in |
|---|---|---|
russh crates.io | All versions | 0.62.4 |
russh crates.io | All versions | 0.62.4 |
How do I fix CVE-2026-73489?
Upgrade russh to 0.62.4 or later.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-73489 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-73489 exists.
Sources
Also known as DEBIAN-CVE-2026-73489, GHSA-cqjc-rmpq-xprq.