CVE-2026-116696
russh's SSH agent server is susceptible to unbound allocations via repeated SSH_AGENT_CONSTRAIN_CONFIRM messages
Impact
russh is a Rust SSH client and server library that includes an SSH agent protocol implementation. Prior to 0.65.0, russh::keys::agent::server::serve in russh/src/keys/agent/server.rs accepts repeated SSH_AGENT_CONSTRAIN_CONFIRM records while adding a key and appends every Constraint::Confirm record to the key's retained constraint vector without a count or memory limit. A process that can connect to the agent socket, including the remote side of a forwarded agent session, can repeatedly add constrained keys and cause renewable memory growth that persists for the process lifetime because keys without a lifetime constraint do not expire. This issue is fixed in version 0.65.0.
Affected packages
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| rust | russh | < 0.65.0 | 0.65.0 |
Affected products
| Vendor | Product | Affected versions |
|---|---|---|
| Eugeny | Russh | before 0.65.0 |
Weakness classification
References
- NVD record
- CVE.org record
- GitHub advisory
- https://github.com/advisories/GHSA-9wfm-jcj8-jfv9
- https://github.com/Eugeny/russh/security/advisories/GHSA-9wfm-jcj8-jfv9
- https://nvd.nist.gov/vuln/detail/CVE-2026-116696
- https://github.com/Eugeny/russh/commit/23aa5d28fe9601c5bdfe9e60b7ec5d4f882c3de6
- https://github.com/Eugeny/russh/releases/tag/v0.65.0