CVE-2026-48107 Russh: Unchecked keyboard-interactive prompt count in client auth path
A malicious SSH server can cause a client crash by sending an excessive prompt count, leading to denial of service in the Russh library.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2026-48107?
CVE-2026-48107 is a medium-severity denial of service vulnerability in Eugeny russh, published on 10 Jun 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official description
Russh is a Rust SSH client & server library. From version 0.37.0 to before version 0.61.0, in the russh client keyboard-interactive authentication path, a malicious SSH server could send a USERAUTH_INFO_REQUEST with an attacker-controlled prompt count, and the client would use that raw count directly in Vec::with_capacity(...) before validating that enough prompt data was actually present in the packet. This issue has been patched in version 0.61.0.
Weakness: CWE-20
Which versions are affected by CVE-2026-48107?
2 open source packages ship an affected version, including russh.
| Package | Affected | Fixed in |
|---|---|---|
russh crates.io | From 0.37.0 | 0.61.0 |
russh crates.io | From 0.37.0 | 0.61.0 |
How do I fix CVE-2026-48107?
Upgrade russh to 0.61.0 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-2026-48107 being exploited?
There is no known exploitation of CVE-2026-48107 in the wild and no public exploit code.
Sources
Also known as DEBIAN-CVE-2026-48107, GHSA-g9g7-5cgw-6v28.