OpenSSH: OpenSSH VerifyHostKeyDNS issue (CVE-2025-26465) #shorts
Summary
Welcome to our cybersecurity podcast, where today we'll be discussing a recent critical vulnerability, CVE-2025-26465, discovered in OpenSSH. This vulnerability affects multiple versions of Red Hat Enterprise Linux and OpenShift Container Platform and poses a serious threat of machine-in-the-middle attacks.
Product details
The vulnerability pertains to OpenSSH when the VerifyHostKeyDNS option is enabled. OpenSSH is a widely used suite of secure networking utilities based on the Secure Shell (SSH) protocol, which provides a secure channel over an unsecured network in a client-server architecture.
Vulnerability type summary
CVE-2025-26465 falls under the 'Detection of Error Condition Without Action' problem type. This vulnerability is linked to how OpenSSH mishandles error codes during specific conditions, potentially allowing attackers to execute machine-in-the-middle attacks and lead to denial-of-service scenarios by exhausting client memory resources.
Details of the vulnerability
Discovered by Qualys TRU, this vulnerability arises in the VerifyHostKeyDNS component of OpenSSH. An attacker can exploit this by impersonating a legitimate server, leading to a machine-in-the-middle attack. The complexity of this attack is high, as it requires the attacker to first exhaust the client's memory resources. Additionally, it allows for weak encryption exploitation by manipulating unknown data.
Conclusion
In conclusion, CVE-2025-26465 highlights a critical security issue within OpenSSH that demands immediate attention. It underscores the importance of proactive vulnerability detection and timely updates to safeguard against potential attacks. Users of OpenSSH, particularly those using Red Hat products, should take urgent measures to mitigate this vulnerability by applying the latest patches and updates.
Watch the full video on YouTube: CVE-2025-26465
Remediation and exploitation details
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