{"id":"CVE-2025-26465","summary":"Openssh: machine-in-the-middle attack if verifyhostkeydns is enabled","details":"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.","modified":"2026-07-16T03:31:13.939646139Z","published":"2025-02-18T18:27:16.843Z","related":["ALSA-2025:16823","ALSA-2025:6993","SUSE-SU-2025:0585-1","SUSE-SU-2025:0605-1","SUSE-SU-2025:0659-1","SUSE-SU-2025:0744-1","SUSE-SU-2025:20160-1","SUSE-SU-2025:20226-1","openSUSE-SU-2025:14820-1"],"database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/26xxx/CVE-2025-26465.json","unresolved_ranges":[{"extracted_events":[{"introduced":"6.8p1"},{"last_affected":"9.9p1"}],"source":"AFFECTED_FIELD"}],"cna_assigner":"redhat","cwe_ids":["CWE-390"]},"references":[{"type":"WEB","url":"http://seclists.org/fulldisclosure/2025/Feb/18"},{"type":"WEB","url":"http://seclists.org/fulldisclosure/2025/May/7"},{"type":"WEB","url":"http://seclists.org/fulldisclosure/2025/May/8"},{"type":"WEB","url":"https://access.redhat.com/downloads/content/package-browser/"},{"type":"WEB","url":"https://access.redhat.com/solutions/7109879"},{"type":"WEB","url":"https://catalog.redhat.com/software/containers/"},{"type":"WEB","url":"https://cert-portal.siemens.com/productcert/html/ssa-082556.html"},{"type":"WEB","url":"https://cert-portal.siemens.com/productcert/html/ssa-585531.html"},{"type":"WEB","url":"https://ftp.openbsd.org/pub/OpenBSD/patches/7.6/common/008_ssh.patch.sig"},{"type":"WEB","url":"https://lists.debian.org/debian-lts-announce/2025/02/msg00020.html"},{"type":"WEB","url":"https://lists.mindrot.org/pipermail/openssh-unix-announce/2025-February/000161.html"},{"type":"WEB","url":"https://seclists.org/oss-sec/2025/q1/144"},{"type":"WEB","url":"https://security-tracker.debian.org/tracker/CVE-2025-26465"},{"type":"WEB","url":"https://ubuntu.com/security/CVE-2025-26465"},{"type":"WEB","url":"https://www.openssh.com/"},{"type":"WEB","url":"https://www.openssh.com/releasenotes.html#9.9p2"},{"type":"WEB","url":"https://www.openwall.com/lists/oss-security/2025/02/18/1"},{"type":"WEB","url":"https://www.openwall.com/lists/oss-security/2025/02/18/4"},{"type":"WEB","url":"https://www.theregister.com/2025/02/18/openssh_vulnerabilities_mitm_dos/"},{"type":"WEB","url":"https://www.vicarius.io/vsociety/posts/cve-2025-26465-detect-vulnerable-openssh"},{"type":"WEB","url":"https://www.vicarius.io/vsociety/posts/cve-2025-26465-mitigate-vulnerable-openssh"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2025:16823"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2025:3837"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2025:6993"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2025:8385"},{"type":"ADVISORY","url":"https://access.redhat.com/security/cve/CVE-2025-26465"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/26xxx/CVE-2025-26465.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2025-26465"},{"type":"ADVISORY","url":"https://security.netapp.com/advisory/ntap-20250228-0003/"},{"type":"REPORT","url":"https://bugzilla.redhat.com/show_bug.cgi?id=2344780"},{"type":"REPORT","url":"https://bugzilla.suse.com/show_bug.cgi?id=1237040"},{"type":"PACKAGE","url":"https://anongit.mindrot.org/openssh.git"},{"type":"ARTICLE","url":"https://blog.qualys.com/vulnerabilities-threat-research/2025/02/18/qualys-tru-discovers-two-vulnerabilities-in-openssh-cve-2025-26465-cve-2025-26466"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/openssh/openssh-portable","events":[{"introduced":"7de4b03a6e4071d454b72927ffaf52949fa34545"},{"last_affected":"6849957945754e6551e515f41e8cf3937cda222d"},{"introduced":"9f82e5a9042f2d872e98f48a876fcab3e25dd9bb"},{"last_affected":"53a80baaebda180f46e6e8571f3ff800e1f5c496"}],"database_specific":{"cpe":["cpe:2.3:a:openbsd:openssh:*:*:*:*:*:*:*:*","cpe:2.3:a:openbsd:openssh:6.8:p1:*:*:*:*:*:*","cpe:2.3:a:openbsd:openssh:9.9:p1:*:*:*:*:*:*"],"extracted_events":[{"introduced":"6.9"},{"last_affected":"9.8"},{"introduced":"6.8-p1"},{"last_affected":"6.8-p1"},{"introduced":"9.9-p1"},{"last_affected":"9.9-p1"}],"source":["CPE_RANGE","CPE_STRING"]}}],"versions":["6.8-p1","9.9-p1","V_9_5_P1","V_9_2_P1","V_9_9_P1","V_9_8_P1","V_9_7_P1","V_9_6_P1","V_9_3_P1","V_9_1_P1","V_9_0_P1","V_8_9_P1","V_8_8_P1","V_8_7_P1","V_8_6_P1","V_8_5_P1","V_8_4_P1","V_8_2_P1","V_8_1_P1","V_8_0_P1","V_7_9_P1","V_7_8_P1","V_7_7_P1","V_7_6_P1","V_7_5_P1","V_7_4_P1","V_7_3_P1","V_7_2_P1","V_7_1_P1","V_7_0_P1","V_6_9_P1"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2025-26465.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N"}]}