CVE-2026-109786

{"id": "CVE-2026-109786", "cveTags": [], "metrics": {"ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-109786", "role": "CISA Coordinator", "options": [{"exploitation": "none"}, {"automatable": "yes"}, {"technicalImpact": "partial"}], "version": "2.0.3", "timestamp": "2026-10-15T15:03:56.691809Z"}}], "cvssMetricV31": [{"type": "Secondary", "source": "cve@mitre.org", "cvssData": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 5.3, "attackVector": "NETWORK", "baseSeverity": "MEDIUM", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L", "integrityImpact": "NONE", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "LOW", "privilegesRequired": "NONE", "confidentialityImpact": "NONE"}, "impactScore": 1.4, "exploitabilityScore": 3.9}]}, "affected": [{"source": "cve@mitre.org", "affectedData": [{"repo": "https://github.com/fail2ban/fail2ban", "vendor": "fail2ban", "modules": ["sshd filter"], "product": "fail2ban", "versions": [{"status": "affected", "version": "0.10.5", "versionType": "custom", "lessThanOrEqual": "1.1.1"}], "platforms": ["Linux", "Unix"], "programFiles": ["config/filter.d/sshd.conf"], "defaultStatus": "unknown"}]}], "published": "2026-10-13T03:16:40.943", "references": [{"url": "https://coredump.ws/repos/mail-hardening.git/", "source": "cve@mitre.org"}, {"url": "https://github.com/fail2ban/fail2ban/commit/ddd879d22664904ace24e1255ac6571808c58187", "source": "cve@mitre.org"}], "vulnStatus": "Awaiting Analysis", "weaknesses": [{"type": "Secondary", "source": "cve@mitre.org", "description": [{"lang": "en", "value": "CWE-117"}]}], "descriptions": [{"lang": "en", "value": "In fail2ban 0.10.5 through 1.1.1 before ddd879d, the sshd filter (config/filter.d/sshd.conf) accepts an \"on <token>\" suffix after the host address. Because OpenSSH logs the offered username verbatim, a remote unauthenticated attacker can use a username such as \"x VICTIM-SOURCE-IP-ADDRESS on\" to make fail2ban associate failed login attempts with an arbitrary source IP address and ban it (e.g., to block logins from a legitimate user). The default filter mode is affected."}], "lastModified": "2026-10-16T19:55:59.740", "sourceIdentifier": "cve@mitre.org"}