Is there a public exploit for CVE-2026-117666?

No public exploit for CVE-2026-117666 was found in Exploit-DB, Metasploit, Nuclei templates or public proof-of-concept repositories. That is an absence of evidence rather than proof that none exists.

How severe is CVE-2026-117666?

CVE-2026-117666 scores CVSS 9.1 (v4.0), rated critical.

9.1 Critical

Improper Validation of Certificate with Host Mismatch vulnerability in deadtrickster sslverifyfun allows an adversary in the middle to…

CVE-2026-117666

Improper Validation of Certificate with Host Mismatch vulnerability in deadtrickster sslverifyfun allows an adversary in the middle to impersonate a TLS peer via a certificate that carries a partial-label wildcard. trymatchwildcard/4 in src/sslverifyhostname.erl anchors only the text before and after the of an identifier such as f.example.net, so the wildcard also consumes dots and the certificate is accepted for f.evil.example.net. RFC 6125 confines a wildcard to the left-most label. The same matcher lets .168.1.1 match the IP literal 192.168.1.1. Whole-label wildcards are matched correctly. Erlang/OTP 20.0 and later check the hostname in ssl before a user verifyfun sees validpeer, so a client that keeps servernameindication set rejects the mismatch regardless. Exposed are clients that disable SNI, servers that verify client certificate hostnames with this library, and direct callers of verifycerthostname/2. This issue affects sslverifyfun: from 1.0.1 before 1.1.8.

Assessment

CVSS: 9.1 (v4.0)
Severity: Critical
Known exploited: Not listed in CISA KEV
Exploit availability: Nothing found in Exploit-DB, Metasploit, Nuclei or public PoC repositories
Published: 30 October 2026
Last updated: 6 November 2026
Weakness: CWE-297
Assigner: 6b3ad84c-e1a6-4bf7-a703-f496b71e49db

CVSS vectorCVSS: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

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