Moderate Security Vulnerability in libssh: Denial of Service and Information Disclosure Risks
Summary
RLSA-2026:62218: Moderate: libssh security update. Affects libssh versions < 0:0.9.6-17.el8_10. Fixed in 0:0.9.6-17.el8_10. How to fix ↓
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Background
libssh is a widely used library that implements the SSH protocol, enabling secure communication between client and server applications. It is essential for various network operations, providing functionalities such as secure file transfers and remote command execution. However, recent vulnerabilities have been identified that could compromise the integrity and availability of applications relying on this library.
Vulnerability Detail
The vulnerabilities in libssh include denial of service attacks through zero advertised channel packet sizes, oversized SFTP read lengths, unchecked ProxyCommand fork() failures, and SFTP responses with unknown request IDs. Additionally, there is a risk of information disclosure via ProxyCommand username expansion and integrity downgrades through OpenSSL AES-GCM tag verification. These vulnerabilities could lead to application crashes, unauthorized access to sensitive information, and potential exploitation by malicious actors.
How To Fix
Minimum fixed version
0:0.9.6-17.el8_10
This is the first release that contains the fix.
sudo dnf update libsshTip — Not sure which version your app runs? Vulert can match this fix to it. Scan free →
Workaround
As a temporary workaround, consider disabling features that utilize ProxyCommand or limit the use of SFTP until the library is updated. This may help mitigate the risks associated with the identified vulnerabilities.
Conclusion
The identified vulnerabilities in libssh pose significant risks, including denial of service and information disclosure. It is crucial to update to the patched version to mitigate these risks and ensure the security of applications relying on this library.
See every vulnerability recorded for libssh →
FAQ
libssh is a library that implements the SSH protocol, allowing secure communication for client and server applications.
The vulnerabilities include denial of service attacks, information disclosure, and integrity downgrades, affecting the library's functionality and security.
You can use the Vulert playground at Vulert Scanner to check if your application is affected by this vulnerability without needing to sign up.
The CVSS score of the vulnerabilities in libssh is 6.5, indicating a moderate level of severity.
You can update libssh by running the command 'sudo yum update libssh' in your terminal, ensuring you have access to the BaseOS repository.
References
Related vulnerabilities
Recent vulnerabilities recorded for libssh.
