Local Code Execution through Argument Injection via dash leading git url parameter in Gemfile.

Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

Severity and exploitation

• CISA KEV Not listed.
• EPSS 0.029, the 87th percentile, on 9 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

Timeline

1. 8 Dec 2021, 18:50 UTC Confirmed by the CVE List
2. 8 Dec 2021, 19:15 UTC Confirmed by NVD

Sources

• GitHub Advisory Database: GHSA-fj7f-vq84-fh43
• OSV: GHSA-fj7f-vq84-fh43
• github.com/rubygems/rubygems/security/advisories/GHSA-fj7f-vq84-fh43
• nvd.nist.gov/vuln/detail/CVE-2021-43809
• github.com/rubygems/rubygems/pull/5142
• github.com/rubygems/rubygems/commit/0fad1ccfe9dd7a3c5b82c1496df3c2b4842870d3
• github.com/rubygems/rubygems/commit/a4f2f8ac17e6ce81c689527a8b6f14381060d95f
• github.com/rubygems/rubygems
• github.com/rubysec/ruby-advisory-db/blob/master/gems/bundler/CVE-2021-43809.yml
• lists.debian.org/debian-lts-announce/2025/05/msg00015.html
• www.sonarsource.com/blog/securing-developer-tools-package-managers

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.