CVE-2025-27088: Reflected Cross-site Scripting (XSS) in template implementation in oxyno-zeta/s3-proxy
Description
oxyno-zeta/s3-proxy is an aws s3 proxy written in go. In affected versions 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 moderate risk to all users. It's possible to inject html elements, including scripts through the folder-list template. 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. This issue has been addressed in version 4.18.1 and all users are advised to upgrade. There are no known workarounds for this vulnerability.
Classification
CVE ID: CVE-2025-27088
CVSS Base Severity: HIGH
CVSS Base Score: 8.4
CVSS Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:N/VA:N/SC:H/SI:H/SA:N
Affected Products
Vendor: oxyno-zeta
Product: s3-proxy
Exploit Prediction Scoring System (EPSS)
EPSS Score: 0.07% (probability of being exploited)
EPSS Percentile: 17.51% (scored less or equal to compared to others)
EPSS Date: 2025-03-21 (when was this score calculated)
References
https://github.com/oxyno-zeta/s3-proxy/security/advisories/GHSA-pp9m-qf39-hxjchttps://github.com/oxyno-zeta/s3-proxy/commit/c611c741ed4872ea3f46232be23bb830f96f9564
https://github.com/oxyno-zeta/s3-proxy/blob/master/templates/folder-list.tpl#L19C21-L19C38