CVE-2021-43809: `Bundler` is a package for managing application dependencies in Ruby

Q: How do I fix CVE-2021-43809?

bundler: upgrade to 2.2.33. Exact commands for each OS are on this page.

Q: Is CVE-2021-43809 being exploited?

CVE-2021-43809 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2021-43809 affect?

CVE-2021-43809 affects bundler. Severity is medium (CVSS 6.7). `Bundler` is a package for managing application dependencies in Ruby. In `bundler` versions before 2.2.33, when working with untrusted and apparently harmless `Gemfile`'s, it is not expected that they lead to execution of external code, unl

Q: How urgent is CVE-2021-43809?

Priority 50/100. Public exploit reference

This month

MEDIUM 6.7UPGRADE

CVE-2021-43809 is a medium-severity flaw (CVSS 6.7) affecting bundler. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

`Bundler` is a package for managing application dependencies in Ruby. In `bundler` versions before 2.2.33, when working with untrusted and apparently harmless `Gemfile`'s, it is not expected that they lead to execution of external code, unless that's explicit in the ruby code inside the `Gemfile` itself. However, if the `Gemfile` includes `gem` entries that use the `git` option with invalid, but seemingly harmless, values with a leading dash, thi

Why this priority

Public exploit reference

A fixed release or distro patch exists.

Risk facts

CVSS score	6.7 (Medium)
Attack vector	Local
Attack complexity	High
Privileges needed	Low
User interaction	Required
EPSS exploit chance	2.9% (top 13%)
CISA exploited list	No
Weakness	CWE-88
Published	2021-12-08
Last modified	2026-06-17

Publisher (CNA): GitHub, Inc. · Vendor: bundler

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2021-12-08 19:15 UTCPublished CVE record published
2026-06-17 04:11 UTCUpdated Record last modified

bundler bundler UPGRADE

Affected: < 2.2.33

Fixed in: 2.2.33

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy bundler || rpm -q bundler || bundler --version

2. UPGRADE to 2.2.33 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade bundler

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade bundler

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2021-43809?

bundler: upgrade to 2.2.33. Exact commands for each OS are on this page.

Is CVE-2021-43809 being exploited?

CVE-2021-43809 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2021-43809 affect?

CVE-2021-43809 affects bundler. Severity is medium (CVSS 6.7). `Bundler` is a package for managing application dependencies in Ruby. In `bundler` versions before 2.2.33, when working with untrusted and apparently harmless `Gemfile`'s, it is not expected that they lead to execution of external code, unl

How urgent is CVE-2021-43809?

Priority 50/100. Public exploit reference

Software pages

Git vulnerabilities · Ruby vulnerabilities

Related CVEs

CVE-2020-36327 HIGH 8.8 UPGRADE MITIGATE Bundler 1.16.0 through 2.2.9 and 2.2.11 through 2.2.16 sometimes chooses a dependency source based on the high

References

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