Description
A vulnerability was found in OpenSSH when the VerifyHostKeyDNS option is enabled. A machine-in-the-middle attack can be performed by a malicious machine impersonating a legit server. This issue occurs due to how OpenSSH mishandles error codes in specific conditions when verifying the host key. For an attack to be considered successful, the attacker needs to manage to exhaust the client's memory resource first, turning the attack complexity high.
CVSS breakdown
CVSS 3.1
Attack Vector
Network
Attack Complexity
High
Privileges Required
None
User Interaction
Required
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
None
Affected products
- debian / debian_linux12.0 – 12.0
- debian / debian_linux11.0 – 11.0
- NETAPP / active_iq_unified_manager
- NETAPP / ontap9 – 9
- OpenBSD / OpenSSH6.9 – 9.8
- OpenBSD / OpenSSH6.8 – 6.8
- OpenBSD / OpenSSH9.9 – 9.9
- OpenBSD / OpenSSH9.9 – 9.9
- RedHat / enterprise_linux9.0 – 9.0
- RedHat / openshift_container_platform4.0 – 4.0
References
- VENDOR_ADVISORYhttps://access.redhat.com/errata/RHSA-2025:16823
- VENDOR_ADVISORYhttps://access.redhat.com/errata/RHSA-2025:3837
- VENDOR_ADVISORYhttps://access.redhat.com/errata/RHSA-2025:6993
- VENDOR_ADVISORYhttps://access.redhat.com/errata/RHSA-2025:8385
- VENDOR_ADVISORYhttps://access.redhat.com/security/cve/CVE-2025-26465
- VENDOR_ADVISORYhttps://access.redhat.com/solutions/7109879
- MISChttps://bugzilla.redhat.com/show_bug.cgi?id=2344780
- MAILING_LISThttps://seclists.org/oss-sec/2025/q1/144
Updated 18m ago · 8 sources