CVE-2025-26465
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.
Predictions
Heuristic predictions, AS-IS, for prioritization only.
Mitigations
No mitigations published for this CVE yet.
The vendor-content worker queues fetches as references arrive (check back in a few minutes). Or — if you've already worked around this in production — publish your fix to the community-verified tier.
✚ Propose a mitigation on Community → Mitigations published via the community go through AI scoring + 2 human reviewers + 7-day silent objection window before landing here withsource_tier=community-verified.
OS impact
SUSE Affected 1 release
| Version | Status | Fixed in |
|---|---|---|
| — | Affected | — |
Debian Mixed 7 releases
| Version | Status | Fixed in |
|---|---|---|
| trixie | Fixed | 1:9.9p2-1 |
| sid | Fixed | 1:9.9p2-1 |
| forky | Fixed | 1:9.9p2-1 |
| bullseye | Fixed | 1:8.4p1-5+deb11u4 |
| bookworm | Fixed | 1:9.2p1-2+deb12u5 |
| 12.0 | Affected | — |
| 11.0 | Affected | — |
Red Hat Mixed 3 releases
| Version | Status | Fixed in |
|---|---|---|
| 9.0 | Affected | — |
| 9 | Fixed | — |
| 8 | Fixed | — |
Rocky Linux Fixed 2 releases
| Version | Status | Fixed in |
|---|---|---|
| 9 | Fixed | — |
| 8 | Fixed | — |
Application impact
| Vendor | Product | Versions | Fixed |
|---|---|---|---|
| openbsd | openssh | {"startIncluding":"6.9","endIncluding":"9.8"} | |
| openbsd | openssh | 6.8 | |
| openbsd | openssh | 9.9 | |
| netapp | active_iq_unified_manager | - | |
| netapp | ontap | 9 | |
| redhat | openshift_container_platform | 4.0 | |
References
- https://access.redhat.com/errata/RHSA-2025:6993
- https://access.redhat.com/errata/RHSA-2025:16823
- https://access.redhat.com/errata/RHSA-2025:3837
- https://access.redhat.com/errata/RHSA-2025:8385
- https://access.redhat.com/security/cve/CVE-2025-26465
- https://access.redhat.com/solutions/7109879
- https://bugzilla.redhat.com/show_bug.cgi?id=2344780
- https://seclists.org/oss-sec/2025/q1/144
- http://seclists.org/fulldisclosure/2025/Feb/18
- http://seclists.org/fulldisclosure/2025/May/7
- http://seclists.org/fulldisclosure/2025/May/8
- https://blog.qualys.com/vulnerabilities-threat-research/2025/02/18/qualys-tru-discovers-two-vulnerabilities-in-openssh-cve-2025-26465-cve-2025-26466
- https://bugzilla.suse.com/show_bug.cgi?id=1237040
- https://ftp.openbsd.org/pub/OpenBSD/patches/7.6/common/008_ssh.patch.sig
- https://lists.debian.org/debian-lts-announce/2025/02/msg00020.html
- https://lists.mindrot.org/pipermail/openssh-unix-announce/2025-February/000161.html
- 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.openssh.com/releasenotes.html#9.9p2
- https://www.openwall.com/lists/oss-security/2025/02/18/1
- https://www.openwall.com/lists/oss-security/2025/02/18/4
- https://www.theregister.com/2025/02/18/openssh_vulnerabilities_mitm_dos/
- https://www.vicarius.io/vsociety/posts/cve-2025-26465-detect-vulnerable-openssh
- https://www.vicarius.io/vsociety/posts/cve-2025-26465-mitigate-vulnerable-openssh
CWEs
CWE-390
Community-verified mitigations for this CVE will appear above when contributors publish them.
Verify integrity in audit chain (admin only). AS-IS.