---
title: "CVE-2026-105221: Gist RubyGem - Improper Certificate Validation"
description: "Gist RubyGem < 6.1.0 contains an improper certificate validation vulnerability caused by VERIFY_NONE setting in http_connection in lib/gist.rb, letting on-path attackers intercept and modify HTTPS traffic, exploit requires network interception capability."
url: https://panop.io/threat-heartbeat/CVE-2026-105221/
---

# CVE-2026-105221 Gist RubyGem - Improper Certificate Validation

Gist RubyGem < 6.1.0 contains an improper certificate validation vulnerability caused by VERIFY\_NONE setting in http\_connection in lib/gist.rb, letting on-path attackers intercept and modify HTTPS traffic, exploit requires network interception capability.

CVSS base score 7.4 /10

High

CISA KEV

Not listed

Public exploit

Proof of concept available

EPSS

0.18% chance of exploitation in 30 days

[View the NVD record ↗](https://nvd.nist.gov/vuln/detail/CVE-2026-105221)

## Details

Type

Improper Certificate Validation

Impact

Information Disclosure, Data Tampering

CVSS vector

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N

Published

4 October 2026

Updated

15 October 2026

Weakness

[CWE-295](https://cwe.mitre.org/data/definitions/295.html)

## Vendor fix

Upgrade to version 6.1.0 or later.

Patching closes this CVE. It does not tell you which of your systems run the affected version, or what else is exposed alongside them.

## References

- [https://nvd.nist.gov/vuln/detail/CVE-2026-105221](https://nvd.nist.gov/vuln/detail/CVE-2026-105221)
- [https://github.com/defunkt/gist/issues/373](https://github.com/defunkt/gist/issues/373)
- [https://www.vulncheck.com/advisories/gist-rubygem-before-6.1.0-disabled-tls-certificate-verification](https://www.vulncheck.com/advisories/gist-rubygem-before-6.1.0-disabled-tls-certificate-verification)
- [https://github.com/defunkt/gist](https://github.com/defunkt/gist)
- [https://github.com/defunkt/gist/blob/v6.0.0/lib/gist.rb#L466-L468](https://github.com/defunkt/gist/blob/v6.0.0/lib/gist.rb#L466-L468)
- [https://github.com/defunkt/gist/commit/07ccc1a6d46e9d36f0e85d0b1c5d795890ae6bcf](https://github.com/defunkt/gist/commit/07ccc1a6d46e9d36f0e85d0b1c5d795890ae6bcf)

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## What this record can't tell you

- Whether you run the affected software, and where
- Whether an attacker can actually reach and exploit it
- The misconfigurations that never get a CVE number
- What it would cost the business, ranked into what to fix first

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