CVE-2026-117666 ssl_verify_fun - Improper Validation of Certificate with Host Mismatch

ssl_verify_fun 1.0.1 before 1.1.8 contains an improper validation of certificate with host mismatch caused by partial-label wildcard matching in try_match_wildcard/4 in src/ssl_verify_hostname.erl, letting man-in-the-middle attackers impersonate TLS peers via certificates with wildcards consuming dots, exploit requires usage of vulnerable ssl_verify_fun with disabled SNI or direct calls to verify_cert_hostname/2.

CVSS base score 9.1 /10
Critical
CISA KEV
Not listed
Public exploit
None known
EPSS
0.19% chance of exploitation in 30 days
View the NVD record ↗

Details

Type
Improper Validation of Certificate with Host Mismatch
Impact
Man In The Middle
CVSS vector
CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Published
30 October 2026
Updated
1 November 2026
Weakness
CWE-297

Vendor fix

Update ssl_verify_fun to version 1.1.8 or later.

Patching closes this CVE. It does not tell you which of your systems run the affected version, or what else is exposed alongside them.

References

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