Unauthenticated stored XSS via forwarded IP header
Published Oct 5, 2021 · Updated Jul 4, 2026
Stored XSS in Activity Logs in Afian FileRun 2021.03.26 allows remote attackers to execute script in an administrator's browser. The login handler records the untrusted X-Forwarded-For header, and the Activity Logs view renders it without neutralizing HTML event handlers. No authentication is required to plant the payload, but an administrator must view or archive the logs; execution can expose or modify users' files through the administrator's session.
Summary
What happened
Stored XSS in Activity Logs in Afian FileRun 2021.03.26 allows remote attackers to execute script in an administrator's browser. The login handler records the untrusted X-Forwarded-For header, and the Activity Logs view renders it without neutralizing HTML event handlers. No authentication is required to plant the payload, but an administrator must view or archive the logs; execution can expose or modify users' files through the administrator's session.
The record
- CVE
- CVE-2021-35503
- Published
- Oct 5, 2021
- Updated
- Jul 4, 2026
- Vendor
- Unknown vendor
- Product
- Unknown product
- Classifications
- CWE-79, T1203
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Oct 5, 2021CVE publishedPublication date reported by the CVE source.
- Jul 4, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
Compare your product and version with the public record. A matching version still requires validation against your environment.
Is a vulnerable build present?
What conditions does exploitation require?
What is affected?
Affected products and versions are unavailable in this record.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- FileRun stored-XSS-to-RCE proof of conceptproof of concept · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Reported exploitation
- Published FileRun XSS-to-RCE exploit chainexploit chain
Technologies
Your stack
See the directory against your own environment.
Your stack
Check the software in your environment
Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.
Book a demo