CVE-2024-27281 is a medium-severity (CVSS 4.5) Deserialization of Untrusted Data vulnerability in rdoc. A fix is available for rdoc — see the affected versions and patch details below.
RDoc RCE vulnerability with .rdoc_options
Exploitation Status
Proof-of-concept exploit code exists
- CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
Exploitation and automatability from CISA’s SSVC triage for CVE-2024-27281.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
CVE-2024-27281 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 377,333 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
rdoc💎rdoc💎rdoc💎rdocReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects RubyGems packages — download data is not available via public APIs for these ecosystems.
Description
An issue was discovered in RDoc 6.3.3 through 6.6.2, as distributed in Ruby 3.x through 3.3.0.
When parsing .rdoc_options (used for configuration in RDoc) as a YAML file, object injection and resultant remote code execution are possible because there are no restrictions on the classes that can be restored.
When loading the documentation cache, object injection and resultant remote code execution are also possible if there were a crafted cache.
We recommend to update the RDoc gem to version 6.6.3.1 or later. In order to ensure compatibility with bundled version in older Ruby series, you may update as follows instead:
- For Ruby 3.0 users: Update to
rdoc6.3.4.1 - For Ruby 3.1 users: Update to
rdoc6.4.1.1 - For Ruby 3.2 users: Update to
rdoc6.5.1.1
You can use gem update rdoc to update it. If you are using bundler, please add gem "rdoc", ">= 6.6.3.1" to your Gemfile.
Note: 6.3.4, 6.4.1, 6.5.1 and 6.6.3 have a incorrect fix. We recommend to upgrade 6.3.4.1, 6.4.1.1, 6.5.1.1 and 6.6.3.1 instead of them.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 💎RubyGems | rdoc | ≥ 6.3.3&&< 6.3.4.1 | 6.3.4.1bundle update rdoc --conservative |
| 💎RubyGems | rdoc | ≥ 6.4.0&&< 6.4.1.1 | 6.4.1.1bundle update rdoc --conservative |
| 💎RubyGems | rdoc | ≥ 6.5.0&&< 6.5.1.1 | 6.5.1.1bundle update rdoc --conservative |
| 💎RubyGems | rdoc | ≥ 6.6.0&&< 6.6.3.1 | 6.6.3.1bundle update rdoc --conservative |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for rdoc, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update rdoc to 6.3.4.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2024-27281 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2024-27281 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2024-27281. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
An attacker would need to provide a maliciously crafted configuration file or documentation cache to a user in order to trigger this vulnerability.
| Product | Fixed in | Advisory |
|---|---|---|
| Red Hat Enterprise Linux 8 | ruby:3.0-8100020240522072634.489197e6 | RHSA-2024:3500 |
| Red Hat Enterprise Linux 8 | ruby:3.1-8100020240510101534.489197e6 | RHSA-2024:3546 |
| Red Hat Enterprise Linux 8 | ruby:3.3-8100020240522151542.489197e6 | RHSA-2024:3670 |
| Red Hat Enterprise Linux 8 | ruby:2.5-8100020240627152904.489197e6 | RHSA-2024:4499 |
| Red Hat Enterprise Linux 9 | ruby:3.1-9040020240503183840.9 | RHSA-2024:3668 |
| Red Hat Enterprise Linux 9 | ruby:3.3-9040020240522171337.9 | RHSA-2024:3671 |
| Red Hat Enterprise Linux 9 | ruby-0:3.0.7-162.el9_4 | RHSA-2024:3838 |
Frequently Asked Questions
Is CVE-2024-27281 in your dependencies?
O3 Security finds CVE-2024-27281 across RubyGems dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.