Description
Russh is a Rust SSH client and server library. Prior to 0.63.1, a connection configured to permit mac=none can negotiate it with a MAC-requiring CTR or CBC block cipher because the selection logic validates needs_mac() only when MAC selection fails. A remote peer can then send a packet with a decrypted length of zero, causing russh/src/cipher/mod.rs to shrink the previously read block before indexing buffer.buffer[16..], which panics and terminates the connection task. This issue is fixed in version 0.63.1.
Published: 2026-09-29
Score: 3.7 Low
EPSS: n/a
KEV: No
Impact: n/a
Action: n/a
AI Analysis

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Remediation

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History

Wed, 30 Sep 2026 00:15:00 +0000

Type Values Removed Values Added
Weaknesses CWE-125
References
Metrics threat_severity

None

threat_severity

Low


Tue, 29 Sep 2026 21:45:00 +0000

Type Values Removed Values Added
First Time appeared Eugeny
Eugeny russh
Vendors & Products Eugeny
Eugeny russh

Tue, 29 Sep 2026 20:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Tue, 29 Sep 2026 18:30:00 +0000

Type Values Removed Values Added
Description Russh is a Rust SSH client and server library. Prior to 0.63.1, a connection configured to permit mac=none can negotiate it with a MAC-requiring CTR or CBC block cipher because the selection logic validates needs_mac() only when MAC selection fails. A remote peer can then send a packet with a decrypted length of zero, causing russh/src/cipher/mod.rs to shrink the previously read block before indexing buffer.buffer[16..], which panics and terminates the connection task. This issue is fixed in version 0.63.1.
Title russh: negotiating a MAC-requiring block cipher (CTR/CBC) with mac=none causes a slice-index-out-of-range panic
Weaknesses CWE-129
References
Metrics cvssV3_1

{'score': 3.7, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L'}


cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-09-29T19:53:30.291Z

Reserved: 2026-09-29T17:25:25.265Z

Link: CVE-2026-102822

cve-icon Vulnrichment

Updated: 2026-09-29T19:53:25.330Z

cve-icon NVD

Status : Deferred

Published: 2026-09-29T19:17:24.190

Modified: 2026-09-29T20:17:17.673

Link: CVE-2026-102822

cve-icon Redhat

Severity : Low

Publid Date: 2026-09-29T18:23:28Z

Links: CVE-2026-102822 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2026-09-29T21:30:08Z

Weaknesses
  • CWE-125

    Out-of-bounds Read

  • CWE-129

    Improper Validation of Array Index