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.
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Tue, 27 Oct 2026 20:45:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| 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. | |
| Title | russh: peer-declared zero maximum packet size permanently stalls channel writes (silent AsyncWrite hang) | |
| Weaknesses | CWE-400 CWE-835 |
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cvssV3_1
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Status: PUBLISHED
Assigner: GitHub_M
Published:
Updated: 2026-10-27T20:25:26.914Z
Reserved: 2026-10-26T21:53:35.166Z
Link: CVE-2026-116774
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Status : Deferred
Published: 2026-10-27T21:18:05.933
Modified: 2026-10-27T21:18:06.060
Link: CVE-2026-116774
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OpenCVE Enrichment
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