Two significant security flaws have been identified in OpenSSH, potentially exposing systems to serious security threats. The Qualys Threat Research Unit has detailed these vulnerabilities:

1. Man-in-the-Middle Vulnerability (CVE-2025-26465)
– Affects OpenSSH versions 6.8p1 to 9.9p1
– CVSS score: 6.8
– Enables attackers to impersonate legitimate servers
– Exploitable when VerifyHostKeyDNS option is enabled
– Particularly impacts FreeBSD systems (2013-2023) where the option was enabled by default

2. Denial-of-Service Vulnerability (CVE-2025-26466)
– Affects OpenSSH versions 9.5p1 to 9.9p1
– CVSS score: 5.9
– Causes excessive memory and CPU consumption
– Can prevent administrative access and disrupt operations
– Exploitable pre-authentication

Impact and Resolution:
– Successful exploitation could lead to compromised SSH sessions and unauthorized data access
– Both vulnerabilities have been patched in OpenSSH 9.9p2
– This follows the earlier regreSSHion vulnerability (CVE-2024-6387) discovered by Qualys
– Users are advised to update to the latest version immediately

Organizations using affected versions should prioritize updates to maintain system security and prevent potential attacks.