CVE-2026-73489: CWE-129: Improper Validation of Array Index in Eugeny russh
Russh is a Rust SSH client & server library. Prior to 0.62.4, an authenticated SSH client can cause a denial of service by sending a pty-req channel request with more than 130 terminal-mode records. The parser in russh/src/server/encrypted.rs stores terminal modes in a fixed 130-entry [(Pty::TTY_OP_END, 0); 130] array but continues increasing the mode count, then constructs an out-of-bounds slice and panics before the application pty_request handler runs. The panic terminates the server session task without causing memory corruption. This issue is fixed in version 0.62.4.
AI Analysis
Technical Summary
The russh library before version 0.62.4 contains an improper validation of array index vulnerability (CWE-129) in its SSH server implementation. When an authenticated client sends a pty-req channel request containing more than 130 terminal-mode records, the server's parser attempts to store these modes in a fixed-size 130-entry array but continues to increment the count beyond this limit. This results in constructing an out-of-bounds slice and causes a panic that terminates the server session task. The panic prevents memory corruption but causes a denial of service by terminating the session prematurely. The vulnerability is addressed in russh version 0.62.4.
Potential Impact
An authenticated SSH client can cause a denial of service by triggering a panic in the server session task, terminating the session. There is no memory corruption or confidentiality/integrity impact reported. The impact is limited to availability disruption of the SSH server session.
Mitigation Recommendations
This vulnerability is fixed in russh version 0.62.4. Users should upgrade to version 0.62.4 or later to remediate the issue. No other mitigation or temporary workaround is indicated.
CVE-2026-73489: CWE-129: Improper Validation of Array Index in Eugeny russh
Description
Russh is a Rust SSH client & server library. Prior to 0.62.4, an authenticated SSH client can cause a denial of service by sending a pty-req channel request with more than 130 terminal-mode records. The parser in russh/src/server/encrypted.rs stores terminal modes in a fixed 130-entry [(Pty::TTY_OP_END, 0); 130] array but continues increasing the mode count, then constructs an out-of-bounds slice and panics before the application pty_request handler runs. The panic terminates the server session task without causing memory corruption. This issue is fixed in version 0.62.4.
CVSS v3.1
Score 4.3medium
Affected software
Eugeny
russh
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Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The russh library before version 0.62.4 contains an improper validation of array index vulnerability (CWE-129) in its SSH server implementation. When an authenticated client sends a pty-req channel request containing more than 130 terminal-mode records, the server's parser attempts to store these modes in a fixed-size 130-entry array but continues to increment the count beyond this limit. This results in constructing an out-of-bounds slice and causes a panic that terminates the server session task. The panic prevents memory corruption but causes a denial of service by terminating the session prematurely. The vulnerability is addressed in russh version 0.62.4.
Potential Impact
An authenticated SSH client can cause a denial of service by triggering a panic in the server session task, terminating the session. There is no memory corruption or confidentiality/integrity impact reported. The impact is limited to availability disruption of the SSH server session.
Mitigation Recommendations
This vulnerability is fixed in russh version 0.62.4. Users should upgrade to version 0.62.4 or later to remediate the issue. No other mitigation or temporary workaround is indicated.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-08-12T19:00:33.735Z
- Cvss Version
- 3.1
- State
- PUBLISHED
Threat ID: 6a7e4130bf8831d539e05264
Added to database: 08/13/2026, 22:12:00 UTC
Last enriched: 08/21/2026, 13:11:54 UTC
Last updated: 09/27/2026, 13:47:47 UTC
Views: 62
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