# CVE-2026-105221 — defunkt gist

> As of 2026-10-04, CVE-2026-105221 is a HIGH-severity vulnerability in defunkt gist, CVSS v3.1 7.4. No Threadlinqs-tracked threat campaign has been attributed to CVE-2026-105221 as of 2026-10-04; the identifier is re-checked against the Threadlinqs threat corpus on every daily ingest.

**Last updated:** 2026-10-04

## What is 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.

The record classifies CVE-2026-105221 under weakness class [CWE-295](https://intel.threadlinqs.com/cwe/CWE-295). Its CVSS v3 base vector states that the flaw is reachable remotely over the network, needs no prior authentication, needs no user interaction, and has high impact on confidentiality, integrity. 1 affected-product entry is recorded, across 1 vendor, listed below. The identifier was first published 1 day ago.

## Severity and exploitation probability

- **CVSS v3.1 base score:** 7.4 — HIGH (`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N`)
- **CVSS v4.0 base score:** 9.1 (`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`)
- **CISA KEV:** Not listed in the CISA Known Exploited Vulnerabilities catalog
- **Threadlinqs priority:** 3.7/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability
- **Published:** 2026-10-04

## Is CVE-2026-105221 being exploited?

It currently carries a trending score of 30 in the Threadlinqs vulnerability feed.

## Affected products and versions

- **defunkt**: gist

## How to fix CVE-2026-105221

No vendor patch reference has been recorded for CVE-2026-105221 in the tracked sources. Follow the references below for a fix, and treat the products listed above as exposed until the vendor states otherwise.

## Threat activity tracking CVE-2026-105221

No threat campaign in the Threadlinqs corpus currently references CVE-2026-105221, in its CVE list or as an indicator. The linkage is recomputed from the live corpus on every daily ingest, so this section fills in as soon as a tracked campaign cites the identifier.

## Sources

Enriched from CVE.org, NVD, GitHub Security Advisories. Last verified by Threadlinqs on 2026-10-05. This product uses the NVD API but is not endorsed or certified by the NVD.

**Vendor advisory and patch**

- [github.com — patch](https://github.com/defunkt/gist/commit/07ccc1a6d46e9d36f0e85d0b1c5d795890ae6bcf)

**Technical analysis**

- [github.com — technical description](https://github.com/defunkt/gist/blob/v6.0.0/lib/gist.rb#L466-L468)

**Third-party advisory**

- [vulncheck.com — third party advisory](https://www.vulncheck.com/advisories/gist-rubygem-before-6.1.0-disabled-tls-certificate-verification)

**Issue tracking and product pages**

- [github.com — issue tracking](https://github.com/defunkt/gist/issues/373)
- [github.com — product](https://github.com/defunkt/gist)

Canonical: https://intel.threadlinqs.com/cve/CVE-2026-105221
Full detection coverage and IOCs for threats exploiting CVE-2026-105221 via the Threadlinqs MCP server (Purple tier): https://intel.threadlinqs.com/mcp