Critical Out of Bounds Read Vulnerability in libssh2: CVE-2019-3862
Summary
ALPINE-CVE-2019-3862: An out of bounds read flaw was discovered in libssh2 before 1.8.1 in the way SSH_MSG_CHANNEL_REQUEST packets with an exit status message and no payload are parsed. Affects libssh2 versions < 1.8.1-r0. Fixed in 1.8.1-r0. How to fix ↓
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Background
libssh2 is a widely used C library that provides an API for implementing the SSH2 protocol in applications. It enables secure communication over unsecured networks and is utilized in various applications for secure file transfers and remote command execution. The library is known for its lightweight design and ease of integration, making it a popular choice among developers. However, it is susceptible to vulnerabilities that can compromise the security of applications relying on it.
Vulnerability Detail
An out of bounds read flaw was discovered in libssh2 before version 1.8.1. This vulnerability arises from the improper handling of SSH_MSG_CHANNEL_REQUEST packets that contain an exit status message but lack a payload. A remote attacker who successfully compromises an SSH server could exploit this flaw to cause a Denial of Service (DoS) or potentially read sensitive data from the client’s memory. The severity of this vulnerability is underscored by its CVSS score of 9.1, indicating a critical risk level.
How To Fix
Minimum fixed version
1.8.1-r0
This is the first release that contains the fix.
sudo apk add --upgrade libssh2Tip — Not sure which version your app runs? Vulert can match this fix to it. Scan free →
Workaround
If an immediate update is not feasible, consider restricting access to the SSH server or implementing network-level controls to limit exposure to potential attackers. Additionally, monitoring logs for unusual activity can help identify attempts to exploit this vulnerability.
Conclusion
CVE-2019-3862 represents a significant security risk for applications utilizing the libssh2 library. It is crucial for developers and system administrators to update to the patched version to safeguard against potential exploits. Regular monitoring and vulnerability assessments can further enhance security posture.
See every vulnerability recorded for libssh2 →
FAQ
CVE-2019-3862 is a critical vulnerability in the libssh2 library that allows for an out of bounds read, potentially leading to Denial of Service or data leakage.
You can use Vulert's playground at Vulert Scanner to check if your application is affected by this vulnerability without needing to sign up.
Failing to address this vulnerability could expose your application to Denial of Service attacks and unauthorized access to sensitive information.
Yes, the patch is available in libssh2 version 1.8.1-r0 and later. Updating to this version will resolve the vulnerability.
The CVSS score of CVE-2019-3862 is 9.1, indicating a critical level of severity.
References
Related vulnerabilities
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