How severe is GHSA-pp9m-qf39-hxjc?

No CVSS score has been assigned to GHSA-pp9m-qf39-hxjc yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by GHSA-pp9m-qf39-hxjc?

GHSA-pp9m-qf39-hxjc affects the following packages: github.com/oxyno-zeta/s3-proxy/cmd/s3-proxy (Go). Ecosystems affected: Go.

How do I fix GHSA-pp9m-qf39-hxjc?

Update github.com/oxyno-zeta/s3-proxy/cmd/s3-proxy to 0.0.0-20250220214310-c611c741ed48 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-pp9m-qf39-hxjc is resolved across your whole dependency graph.

How do I detect GHSA-pp9m-qf39-hxjc in my Go dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/oxyno-zeta/s3-proxy/cmd/s3-proxy, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate GHSA-pp9m-qf39-hxjc if there is no patch (or I can't update yet)?

Escape or sanitise the affected output on the server side rather than relying on client-side filtering, and add a Content-Security-Policy that blocks inline script execution so injected markup cannot run even if it reaches the page.

How does O3 Security protect against GHSA-pp9m-qf39-hxjc?

O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like GHSA-pp9m-qf39-hxjc can be triaged on real exposure rather than presence alone.

Is GHSA-pp9m-qf39-hxjc actively exploited in the wild?

No public exploit code has been indexed for GHSA-pp9m-qf39-hxjc 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-pp9m-qf39-hxjc?

GHSA-pp9m-qf39-hxjc has an EPSS (Exploit Prediction Scoring System) score of 0.5%, placing it in the 40th 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-pp9m-qf39-hxjc?

GHSA-pp9m-qf39-hxjc 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-pp9m-qf39-hxjc published, and has it been updated?

GHSA-pp9m-qf39-hxjc was published on February 20, 2025 and was last updated on September 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.

🐹 Go

Not in CISA KEV

GHSA-pp9m-qf39-hxjc — s3-proxy

Fix: oxyno-zeta/s3-proxy@c611c74

GHSA-pp9m-qf39-hxjc is a Cross-site Scripting (XSS) vulnerability in github.com/oxyno-zeta/s3-proxy/cmd/s3-proxy. A fix is available for github.com/oxyno-zeta/s3-proxy/cmd/s3-proxy — see the affected versions and patch details below.

S3-Proxy allows Reflected Cross-site Scripting (XSS) in template implementation

Also known asCVE-2025-27088GO-2025-3477

Published

Feb 20, 2025

Updated

Sep 10, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Sep 26, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

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 GHSA-pp9m-qf39-hxjc.

EPSS Exploitation Probability

via FIRST.org ↗

0.5%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs40th percentile — riskier than 40% of all scored CVEsHighest risk

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.

Real-World Exposure

1 pkg affected

🐹github.com/oxyno-zeta/s3-proxy/cmd/s3-proxy

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

A Reflected Cross-site Scripting (XSS) vulnerability enables attackers to create malicious URLs that, when visited, inject scripts into the web application. This can lead to session hijacking or phishing attacks on a trusted domain, posing a high risk to all users.

Details

Give all details on the vulnerability. Pointing to the incriminated source code is very helpful for the maintainer. It's possible to inject html elements, including scripts through the folder-list template. It seems like the .Request.URL.Path variable is not escaped.

I did some research and found it might be due to the text/template import being used in the template implementation, instead of the safer html/template.

PoC

Complete instructions, including specific configuration details, to reproduce the vulnerability. Using the default template configuration, the vulnerability can be reproduced with the following steps.

Navigate to https://your-s3-proxy.com/path-not-found and confirm the page looks as follows:
Try inserting an HTML element by changing /path-not-found to /<img src="x"> and confirm the page looks as follows:
Now it should be possible to run any JavaScript by manipulating the onerror property of the img element. This should make the link look like https://your-s3-proxy.com/<img src="x" onerror="alert(1)">. Confirm that going to this URL will in fact shows an alert in the browser.

Impact

The affected template allows users to interact with the URL path provided by the Request.URL.Path variable, which is then rendered directly into the HTML without proper sanitization or escaping. This can be abused by attackers who craft a malicious URL containing injected HTML or JavaScript. When users visit such a URL, the malicious script will be executed in the user's context, leading to potential risks such as:

Session Hijacking: Malicious scripts could be used to steal session cookies or other sensitive information.
Phishing Attacks: JavaScript could be injected to trick users into submitting sensitive information, such as login credentials.

This vulnerability can be exploited by attackers who craft URLs containing malicious payloads, which would then execute in the user's browser when they access the affected page. This poses a high risk to all users who visit such URLs.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐹Go	`github.com/oxyno-zeta/s3-proxy/cmd/s3-proxy`	all versions	0.0.0-20250220214310-c611c741ed48`go get github.com/oxyno-zeta/s3-proxy/cmd/s3-proxy@v0.0.0-20250220214310-c611c741ed48`

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/oxyno-zeta/s3-proxy/cmd/s3-proxy, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update github.com/oxyno-zeta/s3-proxy/cmd/s3-proxy to 0.0.0-20250220214310-c611c741ed48 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-pp9m-qf39-hxjc is resolved across your whole dependency graph.
Workarounds
Escape or sanitise the affected output on the server side rather than relying on client-side filtering, and add a Content-Security-Policy that blocks inline script execution so injected markup cannot run even if it reaches the page.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like GHSA-pp9m-qf39-hxjc can be triaged on real exposure rather than presence alone.

Tailored to GHSA-pp9m-qf39-hxjc. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

### Summary A Reflected Cross-site Scripting (XSS) vulnerability enables attackers to create malicious URLs that, when visited, inject scripts into the web application. This can lead to session hijacking or phishing attacks on a trusted domain, posing a high risk to all users. ### Details _Give all details on the vulnerability. Pointing to the incriminated source code is very helpful for the maintainer._ It's possible to inject html elements, including scripts through the [folder-list template](https://github.com/oxyno-zeta/s3-proxy/blob/master/templates/folder-list.tpl#L19C21-L19C38). It see

O3 Security · Impact-Aware SCA

Is GHSA-pp9m-qf39-hxjc in your dependencies?

O3 Security finds GHSA-pp9m-qf39-hxjc across Go dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.

Scan my dependencies How O3 SCA works