{"id":"CVE-2026-117666","url":"https://www.cyber-defence.io/tools/cve/CVE-2026-117666","generatedAt":"2026-11-04T11:49:45.310Z","title":"Improper Validation of Certificate with Host Mismatch vulnerability in deadtrickster ssl_verify_fun allows an adversary in the middle to impersonate a TLS peer via a certificate that carries a partial-label wildcard. try_match_wildcard/4 in…","description":"Improper Validation of Certificate with Host Mismatch vulnerability in deadtrickster ssl_verify_fun allows an adversary in the middle to impersonate a TLS peer via a certificate that carries a partial-label wildcard. try_match_wildcard/4 in src/ssl_verify_hostname.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.\n\nErlang/OTP 20.0 and later check the hostname in ssl before a user verify_fun sees valid_peer, so a client that keeps server_name_indication set rejects the mismatch regardless. Exposed are clients that disable SNI, servers that verify client certificate hostnames with this library, and direct callers of verify_cert_hostname/2.\n\nThis issue affects ssl_verify_fun: from 1.0.1 before 1.1.8.","published":"2026-10-30T21:16:51.000Z","lastModified":"2026-11-02T19:35:33.000Z","status":"Deferred","sourceIdentifier":"6b3ad84c-e1a6-4bf7-a703-f496b71e49db","cvss":{"version":"4.0","score":9.1,"severity":"CRITICAL","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/M"},"cwe":["CWE-297"],"affected":[],"epss":{"score":0.0019,"percentile":0.08692,"date":"2026-11-03","history":[{"date":"2026-10-31","score":0.0019,"percentile":0.08656}]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"high","text":"High impact if exploited, but EPSS currently rates exploitation as unlikely (0.19%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit."},"changes":[{"kind":"new","label":"New CVE","at":"2026-10-30T21:16:51.000Z","detail":{"score":"9.1","severity":"CRITICAL","publishedAt":"2026-10-30T21:16:51.447Z"},"summary":"New CVE, critical severity (CVSS 9.1)."}],"references":[{"url":"https://cna.erlef.org/cves/CVE-2026-117666.html","source":"6b3ad84c-e1a6-4bf7-a703-f496b71e49db"},{"url":"https://github.com/deadtrickster/ssl_verify_fun.erl/commit/a49ca56923356c7a3981692b23c42ef32c2990e0","source":"6b3ad84c-e1a6-4bf7-a703-f496b71e49db"},{"url":"https://github.com/deadtrickster/ssl_verify_fun.erl/commit/ca34031299cd2e0c98794c0da4ba556b94e39aad","source":"6b3ad84c-e1a6-4bf7-a703-f496b71e49db"},{"url":"https://github.com/deadtrickster/ssl_verify_fun.erl/pull/33","source":"6b3ad84c-e1a6-4bf7-a703-f496b71e49db"},{"url":"https://github.com/deadtrickster/ssl_verify_fun.erl/security/advisories/GHSA-7gw2-hphm-c5px","source":"6b3ad84c-e1a6-4bf7-a703-f496b71e49db"},{"url":"https://osv.dev/vulnerability/EEF-CVE-2026-117666","source":"6b3ad84c-e1a6-4bf7-a703-f496b71e49db"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-117666","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}