CVE-2025-26465
Openssh: machine-in-the-middle attack if verifyhostkeydns is enabled
MEDIUM 6.8EPSS 7.7%
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.
- Affected
- Red Hat · OpenSSH · Red Hat Enterprise Linux 8 · Red Hat Enterprise Linux 9 · Red Hat Enterprise Linux 9.4 Extended Update Support · Red Hat Discovery 1.14 · Red Hat Enterprise Linux 6
- CVSS v3.1 NVD
- 6.8 MEDIUM
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N - EPSS
- 7.72% chance of exploitation in the next 30 days, 95th percentile
- Published
- 2025-02-18
- Updated
- 2026-10-15
Proof-of-concept exploits (1)
- rxerium/CVE-2025-264659★ · 2025-10-14
Security advisories
- https://access.redhat.com/security/cve/CVE-2025-26465
- https://blog.qualys.com/vulnerabilities-threat-research/2025/02/18/qualys-tru-discovers-t…
- https://bugzilla.redhat.com/show_bug.cgi?id=2344780
- https://lists.debian.org/debian-lts-announce/2025/02/msg00020.html
- https://lists.mindrot.org/pipermail/openssh-unix-announce/2025-February/000161.html
- https://seclists.org/oss-sec/2025/q1/144
- https://security-tracker.debian.org/tracker/CVE-2025-26465
- https://security.netapp.com/advisory/ntap-20250228-0003
- https://ubuntu.com/security/CVE-2025-26465
- https://www.openwall.com/lists/oss-security/2025/02/18/1
- https://www.openwall.com/lists/oss-security/2025/02/18/4
- https://www.vicarius.io/vsociety/posts/cve-2025-26465-detect-vulnerable-openssh
- https://www.vicarius.io/vsociety/posts/cve-2025-26465-mitigate-vulnerable-openssh
- https://ftp.openbsd.org/pub/OpenBSD/patches/7.6/common/008_ssh.patch.sig
- https://www.openssh.com/releasenotes.html#9.9p2
- https://bugzilla.suse.com/show_bug.cgi?id=1237040