russh: Unbounded memory allocation in agent protocol server via crafted constraint records

影響: rust:russh <= 0.64.0 → 0.64.1

russh_keys::agent::server::add_key (russh/src/keys/agent/server.rs:271-319) spawns a dedicated tokio task for every 5-byte SSH_AGENT_CONSTRAIN_LIFETIME record attached to an added key, each cloning the key blob and sleeping for the declared lifetime (up to ~136 years). The loop has no per-request task budget, and spawned tasks are not rolled back when the overall request fails. Repeating one constrained add-key message over an agent connection converts wire bytes into resident tasks and…

Read on GitHub Advisory Database

On 10/20/2026, 02:06 AM, GitHub Advisory Database published "russh: Unbounded memory allocation in agent protocol server via crafted constraint records" (type: Advisory). Severity is "Medium" (medium). Related technologies: Rust. CVE: CVE-2026-111061.