CVE-2023-3521
Published: 06 July 2023
Summary
CVE-2023-3521 is a medium-severity Cross-site Scripting (CWE-79) vulnerability in Fossbilling Fossbilling. Its CVSS base score is 6.1 (Medium).
Operationally, ranked in the top 4.5% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.
Deeper analysis
CVE-2023-3521 is a reflected cross-site scripting vulnerability (CWE-79) affecting the FOSSBilling open-source billing application in versions prior to 0.5.4. The flaw resides in user-supplied input handling that is reflected back to the browser without adequate sanitization, allowing malicious scripts to execute in the context of the application origin.
An unauthenticated remote attacker can exploit the issue by crafting a URL containing a malicious payload and inducing a victim to click it. Successful exploitation results in arbitrary JavaScript execution within the victim's session, with the potential to read sensitive data or perform actions on behalf of the user due to the changed scope noted in the CVSS vector.
Public references point to a fix merged in commit 5eb516d4ebcb764db1b2edf9c8d0539e76ebde52 on the FOSSBilling repository; administrators are advised to upgrade to version 0.5.4 or later. The associated Huntr.dev report documents the same remediation path.
The EPSS score has remained flat at 0.1896 with no material increase observed after disclosure.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2023-44178
Vulnerability details
Cross-site Scripting (XSS) - Reflected in GitHub repository fossbilling/fossbilling prior to 0.5.4.
- CWE(s)
Related Threats
No named actor attribution yet. ATT&CK technique mapping in progress for this CVE.
Affected Assets
Mitigating Controls
Likely Mitigating Controls AI
Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.
Penetration testing submits XSS payloads to web applications, detecting cross-site scripting flaws for subsequent remediation.
Validates web inputs to reject script-related content that could produce XSS.
Output validation against expected content can reject or sanitize script content in generated web pages, reducing XSS exploitability.