CVE-2024-27285 is a medium-severity (CVSS 5.4) Cross-site Scripting (XSS) vulnerability in yard. A fix is available for yard — see the affected versions and patch details below.
YARD's default template vulnerable to Cross-site Scripting in generated frames.html
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-2024-27285.
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-2024-27285 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 377,636 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
yardReal-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
Summary
The "frames.html" file within the Yard Doc's generated documentation is vulnerable to Cross-Site Scripting (XSS) attacks due to inadequate sanitization of user input within the JavaScript segment of the "frames.erb" template file.
Details
The vulnerability stems from mishandling user-controlled data retrieved from the URL hash in the embedded JavaScript code within the "frames.erb" template file. Specifically, the script lacks proper sanitization of the hash data before utilizing it to establish the top-level window's location. This oversight permits an attacker to inject malicious JavaScript payloads through carefully crafted URLs.
Snippet from "frames.erb": (v0.9.34)
<script type="text/javascript">
var match = unescape(window.location.hash).match(/^#!(.+)/);
var name = match ? match[1] : '<%= url_for_main %>';
name = name.replace(/^(\w+):\/\//, '').replace(/^\/\//, '');
window.top.location = name;
</script>
(v0.9.35)
<script type="text/javascript">
var match = decodeURIComponent(window.location.hash).match(/^#!(.+)/);
var name = match ? match[1] : '<%= url_for_main %>';
name = name.replace(/^((\w*):)?[\/\\]*/gm, '').trim();
window.top.location.replace(name)
</script>
PoC (Proof of Concept)
To exploit this vulnerability:
- Gain access to the generated Yard Doc.
- Locate and access the "frames.html" file.
- Construct a URL containing the malicious payload in the hash segment, for instance:
#!javascript:xssfor v0.9.34, and#:javascript:xssfor v0.9.35
Impact
This XSS vulnerability presents a substantial threat by enabling an attacker to execute arbitrary JavaScript code within the user's session context. Potential ramifications include session hijacking, theft of sensitive data, unauthorized access to user accounts, and defacement of websites. Any user visiting the compromised page is susceptible to exploitation. It is critical to promptly address this vulnerability to mitigate potential harm to users and preserve the application's integrity.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 💎RubyGems | yard | all versions | 0.9.36bundle update yard --conservative |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for yard, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update yard to 0.9.36 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2024-27285 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-2024-27285 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2024-27285. 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.
Frequently Asked Questions
Is CVE-2024-27285 in your dependencies?
O3 Security finds CVE-2024-27285 across RubyGems dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.