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.
| Version | Base score | Base severity | Vector |
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| Hyperlink | Resource Type |
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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.
| Version | Base score | Base severity | Vector |
|---|---|---|---|
| 3.1 | 6.8 | MEDIUM | CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N |
| CAPEC ID | Description |
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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.
| Event | Date |
|---|---|
| Reported to Red Hat. | 2025-02-10 21:56:03 |
| Made public. | 2025-02-17 00:00:00 |
| Hyperlink | Resource |
|---|---|
| https://access.redhat.com/errata/RHSA-2025:3837 | vendor-advisory x_refsource_REDHAT |
| https://access.redhat.com/errata/RHSA-2025:6993 | vendor-advisory x_refsource_REDHAT |
| https://access.redhat.com/errata/RHSA-2025:8385 | vendor-advisory x_refsource_REDHAT |
| https://access.redhat.com/security/cve/CVE-2025-26465 | vdb-entry x_refsource_REDHAT |
| https://bugzilla.redhat.com/show_bug.cgi?id=2344780 | issue-tracking x_refsource_REDHAT |
| https://seclists.org/oss-sec/2025/q1/144 | N/A |
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| https://seclists.org/oss-sec/2025/q1/144 | exploit |
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.
| Date Added | Due Date | Vulnerability Name | Required Action |
|---|---|---|---|
| N/A |
| Type | Version | Base score | Base severity | Vector |
|---|---|---|---|---|
| Secondary | 3.1 | 6.8 | MEDIUM | CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N |
| Primary | 3.1 | 6.8 | MEDIUM | CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N |