A flaw has been found in libssh in versions prior to 0.9.6. The SSH protocol keeps track of two shared secrets during the lifetime of the session. One of them is called secret_hash and the other session_id. Initially, both of them are the same, but after key re-exchange, previous session_id is kept and used as an input to new secret_hash. Historically, both of these buffers had shared length variable, which worked as long as these buffers were same. But the key re-exchange operation can also change the key exchange method, which can be based on hash of different size, eventually creating "secret_hash" of different size than the session_id has. This becomes an issue when the session_id memory is zeroed or when it is used again during second key re-exchange.
This vulnerability carries a MEDIUM severity rating with a CVSS v3.1 score of 6.5, indicating it can be exploited remotely over the network with relatively low complexity without requiring user interaction requiring only low-level privileges . The vulnerability impacts and availability (service disruption) for affected systems. Impacting 7 products from libssh, from redhat, from redhat and 4 others, organizations running these solutions should prioritize assessment and patching.
Reported in 2021, this vulnerability emerged during an era marked by increased sophistication in supply chain attacks, cloud infrastructure vulnerabilities, and software-as-a-service (SaaS) security challenges. Security practices during this period emphasized zero-trust architectures, container security, and API protection.
2021-08-31T17:15:08.323
2024-11-21T06:22:02.090
Modified
CVSSv3.1: 6.5 (MEDIUM)
AV:N/AC:L/Au:S/C:N/I:N/A:P
8.0
2.9
| Type | Vendor | Product | Version/Range | Vulnerable? |
|---|---|---|---|---|
| Application | libssh | libssh | < 0.9.6 | Yes |
| Application | redhat | virtualization | 4.0 | Yes |
| Operating System | redhat | enterprise_linux | 8.0 | Yes |
| Operating System | debian | debian_linux | 10.0 | Yes |
| Operating System | debian | debian_linux | 11.0 | Yes |
| Operating System | fedoraproject | fedora | 33 | Yes |
| Operating System | fedoraproject | fedora | 34 | Yes |
| Operating System | fedoraproject | fedora | 35 | Yes |
| Application | oracle | mysql_workbench | ≤ 8.0.27 | Yes |
| Application | netapp | cloud_backup | - | Yes |
SecUtils normalizes and enriches National Vulnerability Database (NVD) records by standardizing vendor and product identifiers, aggregating vulnerability metadata from both NVD and MITRE sources, and providing structured context for security teams. For libssh's affected products, we extract Common Platform Enumeration (CPE) data, Common Weakness Enumeration (CWE) classifications, CVSS severity metrics, and reference data to enable rapid vulnerability prioritization and asset correlation. This record contains no exploit code, proof-of-concept instructions, or attack methodologies—only defensive intelligence necessary for patch management, risk assessment, and security operations.