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.
Published: 2026-10-27
Score: 4.3 Medium
EPSS: n/a
KEV: No
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History

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
References
Metrics cvssV3_1

{'score': 4.3, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L'}

Subscriptions

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cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-10-27T20:25:26.914Z

Reserved: 2026-10-26T21:53:35.166Z

Link: CVE-2026-116774

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Deferred

Published: 2026-10-27T21:18:05.933

Modified: 2026-10-27T21:18:06.060

Link: CVE-2026-116774

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

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Weaknesses
  • CWE-400

    Uncontrolled Resource Consumption

  • CWE-835

    Loop with Unreachable Exit Condition ('Infinite Loop')