Description
russh is a Rust SSH client and server library that includes an SSH agent protocol implementation. Prior to 0.65.0, the client Session::process_packet path in russh/src/client/encrypted.rs accepts repeated packets encoded with russh's private msg::EXT_INFO = 7 before authentication, while the standards-compliant EXT_INFO message number 82 does not reach the affected handler. The handle_ext_info function appends every parsed extension name to received_extensions without clearing, deduplicating, or bounding the vector. A malicious SSH server that deliberately sends private message number 7 can therefore retain an unbounded number of attacker-controlled extension names for the session lifetime, causing progressive client memory exhaustion. This issue is fixed in version 0.65.0.
Published: 2026-10-27
Score: 4.3 Medium
EPSS: n/a
KEV: No
Impact: n/a
Action: n/a
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History

Tue, 27 Oct 2026 20:30:00 +0000

Type Values Removed Values Added
Description russh is a Rust SSH client and server library that includes an SSH agent protocol implementation. Prior to 0.65.0, the client Session::process_packet path in russh/src/client/encrypted.rs accepts repeated packets encoded with russh's private msg::EXT_INFO = 7 before authentication, while the standards-compliant EXT_INFO message number 82 does not reach the affected handler. The handle_ext_info function appends every parsed extension name to received_extensions without clearing, deduplicating, or bounding the vector. A malicious SSH server that deliberately sends private message number 7 can therefore retain an unbounded number of attacker-controlled extension names for the session lifetime, causing progressive client memory exhaustion. This issue is fixed in version 0.65.0.
Title russh's SSH client is susceptible to unbounded allocations via EXT_INFO packets
Weaknesses CWE-770
References
Metrics cvssV3_1

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

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cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-10-27T20:23:47.305Z

Reserved: 2026-10-26T21:53:35.165Z

Link: CVE-2026-116773

cve-icon Vulnrichment

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cve-icon NVD

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cve-icon Redhat

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cve-icon OpenCVE Enrichment

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Weaknesses