4.3
MediumCVSS 3.1 · from GitHub_M
CVE-2026-116774
russh: peer-declared zero maximum packet size permanently stalls channel writes (silent AsyncWrite hang)
russh · Uncontrolled resource use · CWE-400Affectedrussh
FixNo fix listed yet.
PublishedOct 27, 20:25 · GitHub_M
ScoredOct 27 · 4.3 · GitHub_M
Exploit code publicNone known · checked 21:18 UTC
ExploitedNone known · CISA KEV checked 22:08 UTC
What we know
No known exploitation. CISA KEV, checked 22:08 UTC.
No public exploit code known. Exploit-DB, Metasploit, Nuclei, checked 21:18 UTC.
An attacker needs network access and an account. CVSS: network, low privileges.
Description
russh is a Rust SSH client and server library that includes an SSH agent protocol implementation. From 0.60.0 until 0.65.0, channel-open parsing accepts a peer-declared maximum_packet_size of zero and passes it into ChannelTx::poll_writable in russh/src/channels/io/tx.rs. The Channel::data, Channel::make_writer, and Channel::into_stream asynchronous write paths then calculate a writable size of zero and remain pending forever because window adjustments cannot satisfy a static zero packet maximum. An authenticated client can strand server writes, and a malicious server can strand client writes, allowing affected tasks, channels, and connections to accumulate without surfacing an error. This issue is fixed in version 0.65.0.
From GitHub_M
Affected and fixed versions
ProductAffectedFixed inrussh>= 0.60.0, < 0.65.0–
Exploit code
Exploit-DBnone knownMetasploitnone knownNucleinone known