ZDF
Sign inSign up

Vulnerabilities

Vulnerability · CVE-2026-117666

ssl_verify_fun: partial-label wildcard certificate matches hostnames across a label boundary

Published Oct 30, 2026 · catalog updated Oct 30, 2026 · ssl_verify_fun: partial-label wildcard certificate

Last checked Nov 6, 2026. A connected source was read within the last 7 days.

Check if you run it

No confirmed exploitation is on record for CVE-2026-117666. EPSS is 0.19%. Act only if a listed version of ssl_verify_fun: partial-label wildcard certificate is installed.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (ssl_verify_fun: partial-label wildcard certificate).
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
Critical9.1
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.19%
Remediation
Advisory link
Affected products
Hex ssl_verify_fun · vendor deadtrickster ssl_verify_fun

## Summary 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. in anchors only the text before and after the of an identifier such as , so the wildcard also consumes dots and the certificate is accepted for . RFC 6125 confines a wildcard to the left-most label. The same matcher lets match the IP literal . Whole-label wildcards are matched correctly. Erlang/OTP 20.0 and later check the hostname in before a user sees , so a client that keeps set rejects the mismatch regardless. Exposed are clients that disable SNI, servers that verify client certificate hostnames with this library, and direct callers of . This issue affects ssl_verify_fun: from 1.0.1 before 1.1.8. ## Details **1. Identifier parsing.** strips trailing dots, tries an exact case-insensitive match, and otherwise calls . That function accepts an identifier with one in the left-most label and at least two labels after it, and classifies it as when the label is exactly . **2. Whole-label wildcard, correct.** For the matcher compares the text after the with the hostname from its first dot onward, so fails because differs from . **3. Partial-label wildcard, incorrect.** For the branch is skipped. then checks only that the hostname ends with and starts with . Nothing checks the span consumed by the , so and pass. RFC 6125 section 6.4.3 limits a wildcard to the left-most label. The guard only rejects internationalized labels and does not help. **4. IP literals.** The reference identifier is treated as a DNS name whatever its shape, so with hostname matches a of through the whole-label branch. RFC 6125 does not apply wildcard matching to IP addresses, and OTP's converts an IP-literal string to an reference that only matches entries. **5. Interaction with Erlang/OTP.** When is used as , OTP 20.0 and later call for before the user fun. In the client rol

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • Hex ssl_verify_fun1.0.1 → 1.1.8
  • vendor deadtrickster ssl_verify_funversion unspecified

How to fix CVE-2026-117666

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-117666. EPSS is 0.19%. Act only if a listed version of ssl_verify_fun: partial-label wildcard certificate is installed.

Which versions are affected?

Compare what you have installed with 1.0.1 → 1.1.8. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-297. EPSS 0.19%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Oct 30, 2026 · GitHub Advisory Database

    Detected

    ## Summary 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. in anchors only the text before and after the of an identifier such as , so the wildcard also consumes dots and the certificate is accepted for . RFC 6125 confines a wildca

  2. Oct 30, 2026 · GitHub Advisory Database

    Fix available

    ssl_verify_fun fixed in 1.1.8

  3. Oct 30, 2026 · GitHub Advisory Database

    Fix available

    ssl_verify_fun fixed in 1.1.8

  4. Oct 30, 2026 · GitHub Advisory Database

    Updated

    ## Summary 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. in anchors only the text before and after the of an identifier such as , so the wildcard also consumes dots and the certificate is accepted for . RFC 6125 confines a wildca

Sources

  • CVE.orgVulnerability recordCVE-2026-117666

    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 onl

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-117666

    30-day exploitation probability 0.19%

    first.org
  • GitHub Advisory DatabasePackage advisoryGHSA-7gw2-hphm-c5px

    GitHub Advisory Database record mirrored by OSV.

    github.com
  • OpenSSF OSV / OSV ScannerPackage advisoryEEF-CVE-2026-117666

    ssl_verify_fun: partial-label wildcard certificate matches hostnames across a label boundary

    osv.dev

References

Freshness

Last verified in this catalog Nov 6, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.

  • FIRST EPSSNov 6, 2026
  • GitHub Advisory DatabaseNov 2, 2026
  • OpenSSF OSV / OSV ScannerNov 2, 2026
  • CVE.orgOct 31, 2026