CVE-2026-109786

Published: Ott 13, 2026 Last Modified: Ott 13, 2026
ExploitDB:
Other exploit source:
Google Dorks:
MEDIUM 5,3
Source: [email protected]
Attack Vector: network
Attack Complexity: low
Privileges Required: none
User Interaction: none
Scope: unchanged
Confidentiality: none
Integrity: none
Availability: low

Description

AI Translation Available

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.

117

Improper Output Neutralization for Logs

Draft
Abstraction: Base Structure: Simple
Common Consequences
Security Scopes Affected:
Integrity Confidentiality Availability Non-Repudiation
Potential Impacts:
Modify Application Data Hide Activities Execute Unauthorized Code Or Commands
Applicable Platforms
All platforms may be affected
Likelihood of Exploit: Medium
View CWE Details
https://coredump.ws/repos/mail-hardening.git/
https://coredump.ws/repos/mail-hardening.git/
https://github.com/fail2ban/fail2ban/commit/ddd879d22664904…
https://github.com/fail2ban/fail2ban/commit/ddd879d22664904ace24e1255ac6571808c…