C-Kermit 8.0.200 before 11.1.515 contains an improper certificate hostname validation vulnerability that allows attackers to impersonate hosts by abusing wildcard matching in dNSName_cmp() in ck_ssl.c. Attackers holding a trusted certificate with over-matching names containing asterisks, question marks, brackets, or empty labels can intercept credentials and data over Telnet, FTP, and HTTP TLS connections.
https://github.com/OpenKermit/ckermit/security/advisories/GHSA-5pc4-gh6q-5h4w
https://github.com/OpenKermit/ckermit/releases/tag/v11.1.515
https://github.com/OpenKermit/ckermit/commit/8c60a2bd70f5a78e77ce5d140a17e7a9cdcd5e60
https://github.com/OpenKermit/ckermit/blob/v11.0.514/ck_ssl.c#L3485
Published: 2026-11-13
Updated: 2026-11-13
Base Score: 7.1
Vector: CVSS2#AV:N/AC:H/Au:N/C:C/I:C/A:N
Severity: High
Base Score: 6.8
Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N
Severity: Medium
Base Score: 7.6
Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N
Severity: High
EPSS: 0.00201