Eugeny russh up to 0.64.x Channel Open Parsing tx.rs ChannelTx::poll_writable maximum_packet_size resource consumption

Summaryinfo

A vulnerability was found in Eugeny russh up to 0.64.x. It has been rated as problematic. This affects the function ChannelTx::poll_writable of the file russh/src/channels/io/tx.rs of the component Channel Open Parsing. This manipulation of the argument maximum_packet_size causes resource consumption. This vulnerability is tracked as CVE-2026-116774. The attack is possible to be carried out remotely. No exploit exists. Upgrading the affected component is advised.

Detailsinfo

A vulnerability has been found in Eugeny russh up to 0.64.x and classified as problematic. Affected by this vulnerability is the function ChannelTx::poll_writable of the file russh/src/channels/io/tx.rs of the component Channel Open Parsing. The manipulation of the argument maximum_packet_size with an unknown input leads to a resource consumption vulnerability. The CWE definition for the vulnerability is CWE-400. The product does not properly control the allocation and maintenance of a limited resource, thereby enabling an actor to influence the amount of resources consumed, eventually leading to the exhaustion of available resources. As an impact it is known to affect availability. The summary by CVE is:

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.

It is possible to read the advisory at github.com. This vulnerability is known as CVE-2026-116774 since 10/26/2026. The exploitation appears to be easy. The attack can be launched remotely. Technical details of the vulnerability are known, but there is no available exploit. The attack technique deployed by this issue is T1499 according to MITRE ATT&CK.

Upgrading to version 0.65.0 eliminates this vulnerability.

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Productinfo

Vendor

• Eugeny

Name

• russh

Version

• 0.1
• 0.2
• 0.3
• 0.4
• 0.5
• 0.6
• 0.7
• 0.8
• 0.9
• 0.10
• 0.11
• 0.12
• 0.13
• 0.14
• 0.15
• 0.16
• 0.17
• 0.18
• 0.19
• 0.20
• 0.21
• 0.22
• 0.23
• 0.24
• 0.25
• 0.26
• 0.27
• 0.28
• 0.29
• 0.30
• 0.31
• 0.32
• 0.33
• 0.34
• 0.35
• 0.36
• 0.37
• 0.38
• 0.39
• 0.40
• 0.41
• 0.42
• 0.43
• 0.44
• 0.45
• 0.46
• 0.47
• 0.48
• 0.49
• 0.50
• 0.51
• 0.52
• 0.53
• 0.54
• 0.55
• 0.56
• 0.57
• 0.58
• 0.59
• 0.60
• 0.61
• 0.62
• 0.63
• 0.64

Website

• Product: https://github.com/Eugeny/russh/

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