Vulnerability in Defunkt Gist
CVE-2026-105221
The gist RubyGem before 6.1.0 contains an improper certificate validation vulnerability that allows on-path attackers to intercept HTTPS traffic because http_connection in lib/gist.rb sets VERIFY_NONE. Attackers can present any certificate to read or modify GitHub API traffic, stealing OAuth tokens and login credentials to read and modify the victim's gists.
Vulnerability class: Improper Certificate Validation
Published .
CVSS v3 metric
CVSS v3 base score 7.4 (High). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N.
EPSS exploit prediction
No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.
Affected products
Weakness classification (CWE)
References
- github.com/defunkt/gist/issues/373 (issue-tracking)
- github.com/defunkt/gist (product)
- github.com/defunkt/gist/blob/v6.0.0/lib/gist.rb (technical-description)
- github.com/defunkt/gist/commit/07ccc1a6d46e9d36f0e85d0b1c5d795890ae6bcf (patch)
- www.vulncheck.com/advisories/gist-rubygem-before-6.1.0-disabled-tls-certificate… (third-party-advisory)
Frequently asked questions
- What is CVE-2026-105221?
- CVE-2026-105221 is a high-severity vulnerability in Defunkt Gist, classified under Improper Certificate Validation. CVSS score: 7.4/10. Published 2026-10-04.
- How severe is CVE-2026-105221?
- High severity. CVSS v3 base score is 7.4 out of 10.