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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.

PUBLISHED Reserved 2025-02-10 | Published 2025-02-18 | Updated 2025-10-23 | Assigner redhat




MEDIUM: 6.8CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N

Problem types

Detection of Error Condition Without Action

Product status

Default status
unaffected

6.8p1 (custom)
affected

Default status
affected

0:8.0p1-26.el8_10 (rpm) before *
unaffected

Default status
affected

0:8.0p1-26.el8_10 (rpm) before *
unaffected

Default status
affected

0:8.7p1-45.el9 (rpm) before *
unaffected

Default status
affected

0:8.7p1-45.el9 (rpm) before *
unaffected

Default status
affected

0:8.7p1-38.el9_4.5 (rpm) before *
unaffected

Default status
affected

sha256:ad1045aa0de937c3a6969ec377f7bfeda9a44ee434a954e8245e9840316ffc1c (rpm) before *
unaffected

Default status
unaffected

Default status
unknown

Default status
unknown

Default status
affected

Timeline

2025-02-10:Reported to Red Hat.
2025-02-17:Made public.

References

access.redhat.com/errata/RHSA-2025:16823 (RHSA-2025:16823) vendor-advisory

access.redhat.com/errata/RHSA-2025:3837 (RHSA-2025:3837) vendor-advisory

access.redhat.com/errata/RHSA-2025:6993 (RHSA-2025:6993) vendor-advisory

access.redhat.com/errata/RHSA-2025:8385 (RHSA-2025:8385) vendor-advisory

access.redhat.com/security/cve/CVE-2025-26465 vdb-entry

access.redhat.com/solutions/7109879

bugzilla.redhat.com/show_bug.cgi?id=2344780 (RHBZ#2344780) issue-tracking

seclists.org/oss-sec/2025/q1/144

cve.org (CVE-2025-26465)

nvd.nist.gov (CVE-2025-26465)

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