Openssh: machine-in-the-middle attack if verifyhostkeydns is enabled
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | ||||||
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| unaffected |
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| Red Hat | Red Hat Enterprise Linux 8 | affected |
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| Red Hat | Red Hat Enterprise Linux 8 | affected |
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| Red Hat | Red Hat Enterprise Linux 9 | affected |
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| Red Hat | Red Hat Enterprise Linux 9 | affected |
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| Red Hat | Red Hat Enterprise Linux 9.4 Extended Update Support | affected |
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| Red Hat | Red Hat Discovery 1.14 | affected |
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| Red Hat | Red Hat Enterprise Linux 10 | unaffected | — | ||||||
| Red Hat | Red Hat Enterprise Linux 6 | unknown | — | ||||||
| Red Hat | Red Hat Enterprise Linux 7 | unknown | — | ||||||
| Red Hat | Red Hat OpenShift Container Platform 4 | affected | — |
Configuration 1 [-]
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Configuration 2 [-]
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| Package | CPE | Advisory | Released Date |
|---|---|---|---|
| Red Hat Enterprise Linux 9 | |||
| openssh-0:8.7p1-45.el9 | cpe:/a:redhat:enterprise_linux:9 | RHSA-2025:6993 | 2025-05-13T00:00:00Z |
| openssh-0:8.7p1-45.el9 | cpe:/o:redhat:enterprise_linux:9 | RHSA-2025:6993 | 2025-05-13T00:00:00Z |
| Red Hat Enterprise Linux 9.4 Extended Update Support | |||
| openssh-0:8.7p1-38.el9_4.5 | cpe:/a:redhat:rhel_eus:9.4 | RHSA-2025:3837 | 2025-04-14T00:00:00Z |
| Red Hat Discovery 1.14 | |||
| registry.redhat.io/discovery/discovery-server-rhel9:sha256:f33991d766b618a128fb99fbe4f9b61c5004f7c6aa73b2b38e28d59e56c64d63 | cpe:/a:redhat:discovery:1.14::el9 | RHSA-2025:8385 | 2025-06-02T00:00:00Z |
No data available yet.
Vendor Workaround
This issue can be mitigated by disabling VerifyHostKeyDNS by setting that option to 'no' in an SSH client configuration file (such as /etc/ssh/ssh_config, ~/.ssh/config, or one of the files in the /etc/ssh/ssh_config.d/ directory). This is the default configuration in Red Hat Enterprise Linux. For configurations that require VerifyHostKeyDNS to be enabled (set to either 'yes' or 'ask'), mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
| Source | ID | Title |
|---|---|---|
Debian DLA |
DLA-4057-1 | openssh security update |
Debian DSA |
DSA-5868-1 | openssh security update |
Ubuntu USN |
USN-7270-1 | OpenSSH vulnerabilities |
Ubuntu USN |
USN-7270-2 | OpenSSH vulnerability |
No CVSS v4.0
No CVSS v3.0
No CVSS v2
This CVE is not in the KEV list.
Exploit prediction score: 7.7% (7.723% probability within 30 days)
| Type | Values Removed | Values Added |
|---|---|---|
| First Time appeared |
Redhat rhel Els
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| CPEs | cpe:/o:redhat:enterprise_linux:6 cpe:/o:redhat:enterprise_linux:7 |
cpe:/a:redhat:enterprise_linux:10 cpe:/o:redhat:rhel_els:6 cpe:/o:redhat:rhel_els:7 |
| Vendors & Products |
Redhat rhel Els
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| Type | Values Removed | Values Added |
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| Type | Values Removed | Values Added |
|---|---|---|
| CPEs | cpe:/a:redhat:enterprise_linux:8::appstream cpe:/o:redhat:enterprise_linux:8::baseos |
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| References |
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| Type | Values Removed | Values Added |
|---|---|---|
| First Time appeared |
Redhat discovery
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| CPEs | cpe:/a:redhat:discovery:1.14::el9 | |
| Vendors & Products |
Redhat discovery
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| References |
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| Type | Values Removed | Values Added |
|---|---|---|
| CPEs | cpe:/o:redhat:enterprise_linux:10 |
| Type | Values Removed | Values Added |
|---|---|---|
| CPEs | cpe:/a:redhat:enterprise_linux:9 cpe:/o:redhat:enterprise_linux:9 |
| Type | Values Removed | Values Added |
|---|---|---|
| CPEs | cpe:/a:redhat:enterprise_linux:9::appstream cpe:/o:redhat:enterprise_linux:9::baseos |
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| References |
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| Type | Values Removed | Values Added |
|---|---|---|
| CPEs | cpe:/a:redhat:rhel_eus:9.4 |
| Type | Values Removed | Values Added |
|---|---|---|
| First Time appeared |
Debian
Debian debian Linux Netapp Netapp active Iq Unified Manager Netapp ontap Openbsd Openbsd openssh Redhat openshift Container Platform |
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| CPEs | cpe:2.3:a:netapp:active_iq_unified_manager:-:*:*:*:*:vmware_vsphere:*:* cpe:2.3:a:netapp:ontap:9:*:*:*:*:*:*:* cpe:2.3:a:openbsd:openssh:*:*:*:*:*:*:*:* cpe:2.3:a:openbsd:openssh:6.8:p1:*:*:*:*:*:* cpe:2.3:a:openbsd:openssh:9.9:-:*:*:*:*:*:* cpe:2.3:a:openbsd:openssh:9.9:p1:*:*:*:*:*:* cpe:2.3:a:redhat:openshift_container_platform:4.0:*:*:*:*:*:*:* cpe:2.3:o:debian:debian_linux:11.0:*:*:*:*:*:*:* cpe:2.3:o:debian:debian_linux:12.0:*:*:*:*:*:*:* cpe:2.3:o:redhat:enterprise_linux:9.0:*:*:*:*:*:*:* |
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| Vendors & Products |
Debian
Debian debian Linux Netapp Netapp active Iq Unified Manager Netapp ontap Openbsd Openbsd openssh Redhat openshift Container Platform |
| Type | Values Removed | Values Added |
|---|---|---|
| First Time appeared |
Redhat rhel Eus
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| CPEs | cpe:/a:redhat:rhel_eus:9.4::appstream cpe:/o:redhat:rhel_eus:9.4::baseos |
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| Vendors & Products |
Redhat rhel Eus
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| Metrics |
ssvc
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| Metrics |
threat_severity
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threat_severity
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| 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. | |
| Title | Openssh: machine-in-the-middle attack if verifyhostkeydns is enabled | |
| First Time appeared |
Redhat
Redhat enterprise Linux Redhat openshift |
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| Weaknesses | CWE-390 | |
| CPEs | cpe:/a:redhat:openshift:4 cpe:/o:redhat:enterprise_linux:6 cpe:/o:redhat:enterprise_linux:7 cpe:/o:redhat:enterprise_linux:8 cpe:/o:redhat:enterprise_linux:9 |
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| Vendors & Products |
Redhat
Redhat enterprise Linux Redhat openshift |
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| References |
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| Metrics |
cvssV3_1
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