Memory Management Flaw in libssh Versions Impacting Secure Shell Protocols
CVE-2021-3634

6.5MEDIUM

Key Information:

Vendor

Libssh

Status
Libssh
Vendor
CVE Published:
31 August 2021

What is CVE-2021-3634?

A vulnerability exists in libssh versions prior to 0.9.6 due to improper management of session identifiers during SSH protocol key re-exchange. The flawed memory handling allows the session_id buffer to retain previous values, leading to potential issues when a new secret_hash of differing size is created. This misalignment can compromise the integrity of secure sessions, allowing attackers to exploit the SSH protocol more effectively if not addressed.

Affected Version(s)

libssh libssh 0.9.6

References

https://bugzilla.redhat.com/show_bug.cgi?id=1978810
https://www.debian.org/security/2021/dsa-4965
vendor-advisory
https://lists.fedoraproject.org/archives/list/package-ann...
vendor-advisory

CVSS V3.1

Score:
6.5
Severity:
MEDIUM
Confidentiality:
None
Integrity:
None
Availability:
None
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
Low
User Interaction:
None
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

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