How severe is GHSA-4wx8-5gm2-2j97?

GHSA-4wx8-5gm2-2j97 has a CVSS score of 7.6/10, rated HIGH. Immediate patching is strongly recommended.

Which packages are affected by GHSA-4wx8-5gm2-2j97?

GHSA-4wx8-5gm2-2j97 affects the following packages: github.com/filebrowser/filebrowser/v2 (Go), github.com/filebrowser/filebrowser (Go). Ecosystems affected: Go.

How do I fix GHSA-4wx8-5gm2-2j97?

Update github.com/filebrowser/filebrowser/v2 to 2.33.7 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-4wx8-5gm2-2j97 is resolved across your whole dependency graph.

How do I detect GHSA-4wx8-5gm2-2j97 in my Go dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/filebrowser/filebrowser/v2. 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-4wx8-5gm2-2j97 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-4wx8-5gm2-2j97?

O3 pinpoints whether GHSA-4wx8-5gm2-2j97 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-4wx8-5gm2-2j97 actively exploited in the wild?

No public exploit code has been indexed for GHSA-4wx8-5gm2-2j97 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-4wx8-5gm2-2j97?

GHSA-4wx8-5gm2-2j97 has an EPSS (Exploit Prediction Scoring System) score of 0.3%, placing it in the 18th 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-4wx8-5gm2-2j97?

GHSA-4wx8-5gm2-2j97 is classified as Cross-site Scripting (XSS) (CWE-79), CWE-80 (CWE-80). These weakness types 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-4wx8-5gm2-2j97 published, and has it been updated?

GHSA-4wx8-5gm2-2j97 was published on June 27, 2025 and was last updated on August 4, 2025. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐹 Go

GHSA-4wx8-5gm2-2j97

HIGH

filebrowser allows Stored Cross-Site Scripting through the Markdown preview function

Also known asCVE-2025-52902GO-2025-3784

Published

Jun 27, 2025

Updated

Aug 4, 2025

Affected

2 pkgs

Patched

1 / 2

Exploits

None indexed

EPSS Exploitation Probability

via FIRST.org ↗

0.3%probability of exploitation in next 30 days

Lower Risk18th percentile+0.16%

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

2 pkgs affected

🐹github.com/filebrowser/filebrowser/v2🐹github.com/filebrowser/filebrowser

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.

Description

Summary

The Markdown preview function of File Browser v2.32.0 is vulnerable to Stored Cross-Site-Scripting (XSS). Any JavaScript code that is part of a Markdown file uploaded by a user will be executed by the browser

Impact

A user can upload a malicious Markdown file to the application which can contain arbitrary HTML code. If another user within the same scope clicks on that file, a rendered preview is opened. JavaScript code that has been included will be executed.

Malicious actions that are possible include:

Obtaining a user's session token
Elevating the attacker's privileges, if the victim is an administrator (e.g., gaining command execution rights)

Vulnerability Description

Most Markdown parsers accept arbitrary HTML in a document and try rendering it accordingly. For instance, if one creates a file called xss.md with the following content:

# Hallo

<b>foo</b>

<img src="xx" onerror=alert(9)>
<i>bar</i>

Bold and italic text will be rendered. Also, the renderer used in File Browser will try to display the image and execute the code in the onerror event handler.

Proof of Concept

The screenshot shows that the code from the file mentioned above has actually been executed in the victim's browser:

JavaScript code being executed in the Markdown Preview

Recommended Countermeasures

The most thorough fix would be to reconfigure the application's Markdown parser to ignore all HTML elements and only render rich text which is part of the Markdown specification. If HTML rendering is considered to be a required feature, an HTML sanitizer like DOMPurify should be used, preferably in conjunction with a Content Security Policy (CSP).

Timeline

2025-03-25 Identified the vulnerability in version 2.32.0
2025-04-11 Contacted the project
2025-04-18 Vulnerability disclosed to the project
2025-06-25 Uploaded advisories to the project's GitHub repository
2025-06-26 CVE ID assigned by GitHub
2025-06-26 Fix released with version 2.33.7

References

Credits

Mathias Tausig (SBA Research)

Affected Packages

2 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐹Go	`github.com/filebrowser/filebrowser/v2`	all versions	2.33.7
🐹Go	`github.com/filebrowser/filebrowser`	all versions	No fix

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/filebrowser/filebrowser/v2. 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 github.com/filebrowser/filebrowser/v2 to 2.33.7 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-4wx8-5gm2-2j97 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-4wx8-5gm2-2j97 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-4wx8-5gm2-2j97. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

## Summary ## The Markdown preview function of File Browser v2.32.0 is vulnerable to *Stored Cross-Site-Scripting (XSS)*. Any JavaScript code that is part of a Markdown file uploaded by a user will be executed by the browser ## Impact ## A user can upload a malicious Markdown file to the application which can contain arbitrary HTML code. If another user within the same scope clicks on that file, a rendered preview is opened. JavaScript code that has been included will be executed. Malicious actions that are possible include: * Obtaining a user's session token * Elevating the attacke

O3 Security · Impact-Aware SCA

Is GHSA-4wx8-5gm2-2j97 in your dependencies?

O3 detects GHSA-4wx8-5gm2-2j97 across Go 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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