How severe is GHSA-whrj-4476-wvmp?

GHSA-whrj-4476-wvmp has a CVSS score of 5.4/10, rated MEDIUM. Review your exposure and patch according to your risk tolerance.

Which packages are affected by GHSA-whrj-4476-wvmp?

GHSA-whrj-4476-wvmp affects the following packages: rack (RubyGems), rack (RubyGems), rack (RubyGems). Ecosystems affected: RubyGems.

How do I fix GHSA-whrj-4476-wvmp?

Update rack to 2.2.22 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-whrj-4476-wvmp is resolved across your whole dependency graph.

How do I detect GHSA-whrj-4476-wvmp in my RubyGems dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for rack. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.

How do I mitigate GHSA-whrj-4476-wvmp if there is no patch (or I can't update yet)?

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 does O3 Security protect against GHSA-whrj-4476-wvmp?

O3 pinpoints whether GHSA-whrj-4476-wvmp is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Is GHSA-whrj-4476-wvmp actively exploited in the wild?

No public exploit code has been indexed for GHSA-whrj-4476-wvmp yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for GHSA-whrj-4476-wvmp?

GHSA-whrj-4476-wvmp has an EPSS (Exploit Prediction Scoring System) score of 0.2%, placing it in the 13th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is GHSA-whrj-4476-wvmp?

GHSA-whrj-4476-wvmp is classified as Cross-site Scripting (XSS) (CWE-79). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation. This is a high-impact weakness class that often enables remote code execution or data exposure.

When was GHSA-whrj-4476-wvmp published, and has it been updated?

GHSA-whrj-4476-wvmp was published on February 17, 2026 and was last updated on March 10, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

💎 RubyGems

GHSA-whrj-4476-wvmp

MEDIUM

Stored XSS in Rack::Directory via javascript: filenames rendered into anchor href

Also known asCVE-2026-25500

Published

Feb 17, 2026

Updated

Mar 10, 2026

Affected

3 pkgs

Patched

3 / 3

Exploits

None indexed

EPSS Exploitation Probability

via FIRST.org ↗

0.2%probability of exploitation in next 30 days

Lower Risk13th percentile+0.20%

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.

Blast Radius

3 pkgs affected

💎rack💎rack💎rack

Real-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

Rack::Directory generates an HTML directory index where each file entry is rendered as a clickable link. If a file exists on disk whose basename begins with the javascript: scheme (e.g. javascript:alert(1)), the generated index includes an anchor whose href attribute is exactly javascript:alert(1). Clicking this entry executes arbitrary JavaScript in the context of the hosting application.

This results in a client-side XSS condition in directory listings generated by Rack::Directory.

Details

Rack::Directory renders directory entries using an HTML row template similar to:

<a href='%s'>%s</a>

The %s placeholder is populated directly with the file’s basename. If the basename begins with javascript:, the resulting HTML contains an executable JavaScript URL:

<a href='javascript:alert(1)'>javascript:alert(1)</a>

Because the value is inserted directly into the href attribute without scheme validation or normalization, browsers interpret it as a JavaScript URI. When a user clicks the link, the JavaScript executes in the origin of the Rack application.

Impact

If Rack::Directory is used to expose filesystem contents over HTTP, an attacker who can create or upload files within that directory may introduce a malicious filename beginning with javascript:.

When a user visits the directory listing and clicks the entry, arbitrary JavaScript executes in the application's origin. Exploitation requires user interaction (clicking the malicious entry).

Mitigation

Update to a patched version of Rack in which Rack::Directory prefixes generated anchors with a relative path indicator (e.g. ./filename).
Avoid exposing user-controlled directories via Rack::Directory.
Apply a strict Content Security Policy (CSP) to reduce impact of potential client-side execution issues.
Where feasible, restrict or sanitize uploaded filenames to disallow dangerous URI scheme prefixes.

HackerOne profile: https://hackerone.com/thesmartshadow

GitHub account owner: Ali Firas (@thesmartshadow)

Affected Packages

3 total 3 fixed

Ecosystem	Package	Vulnerable range	Fix
💎RubyGems	`rack`	all versions	2.2.22
💎RubyGems	`rack`	≥ 3.0.0.beta1&&< 3.1.20	3.1.20
💎RubyGems	`rack`	≥ 3.2.0&&< 3.2.5	3.2.5

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for rack. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update rack to 2.2.22 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-whrj-4476-wvmp 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 pinpoints whether GHSA-whrj-4476-wvmp is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Tailored to GHSA-whrj-4476-wvmp. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

## Summary `Rack::Directory` generates an HTML directory index where each file entry is rendered as a clickable link. If a file exists on disk whose basename begins with the `javascript:` scheme (e.g. `javascript:alert(1)`), the generated index includes an anchor whose `href` attribute is exactly `javascript:alert(1)`. Clicking this entry executes arbitrary JavaScript in the context of the hosting application. This results in a client-side XSS condition in directory listings generated by `Rack::Directory`. ## Details `Rack::Directory` renders directory entries using an HTML row template si

O3 Security · Impact-Aware SCA

Is GHSA-whrj-4476-wvmp in your dependencies?

O3 detects GHSA-whrj-4476-wvmp across RubyGems dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

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