Bug 2573256 (CVE-2026-129117)

Summary: CVE-2026-129117 ckermit: ckermit: Server impersonation via improper certificate validation
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedKeywords: Security
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OS: Linux   
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A flaw was found in ckermit. A machine-in-the-middle attacker can intercept sensitive communications and credentials by impersonating legitimate Telnet servers. This issue occurs because the client fails to perform hostname verification during Telnet SSL authentication, allowing an attacker presenting a certificate issued by any trusted Certificate Authority (CA) to view and manipulate session data.
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Description OSIDB Bzimport 2026-11-13 16:32:42 UTC 
C-Kermit 8.0.200 before 11.1.515 contains an improper certificate validation vulnerability that allows machine-in-the-middle attackers to impersonate Telnet servers because ssl_reply() never calls ssl_check_server_name(). Attackers can refuse START-TLS, offer Telnet AUTHENTICATION SSL, and present any trusted CA certificate to capture user credentials and session data.