CVE-2026-117666：ssl_verify_fun 部分萬用字元證書跨標籤邊界匹配主機名
CVE-2026-117666 - ssl_verify_fun: partial-label wildcard certificate matches hostnames across a label boundary
CVE-2026-117666 漏洞導致 deadtrickster ssl_verify_fun 允許中間人使用部分萬用字元證書冒充 TLS 對等方。
- 漏洞原理：
try_match_wildcard/4錯誤匹配*位置，使f*.example.net能匹配f.evil.example.net，違反 RFC 6125。
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. Erlang/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. This issue affects ssl_verify_fun: from 1.0.1 before 1.1.8.
Impact
Affected Products
The following products are affected by CVE-2026-117666
vulnerability.
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No affected product recoded yet
The Common Vulnerability Scoring System is a standardized framework for assessing the severity of vulnerabilities in software and systems. We collect and displays CVSS scores from various sources for each CVE.
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 4.0 | CRITICAL | 6b3ad84c-e1a6-4bf7-a703-f496b71e49db |
Update the ssl_verify_fun library to a version that properly validates TLS peer certificates and hostnames.
- Update ssl_verify_fun to version 1.1.8 or later.
- Ensure server_name_indication is enabled on clients.
- Verify client certificate hostnames are correctly validated.
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