CVE-2021-1239 Cisco Firepower Management Center Stored Cross-Site Scripting Vulnerabilities
Authenticated attackers can inject malicious scripts into the Cisco FMC interface, potentially executing code or stealing data from other users.
- Exploited in the wild
- Not known
- Login needed
- An administrator
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- None listed
What is CVE-2021-1239?
CVE-2021-1239 is a medium-severity cross-site scripting vulnerability in Cisco Secure Firewall Management Center, published on 13 Jan 2021. An attacker needs administrator access to exploit it, and only if a user opens a file or follows a link.
Official description
Multiple vulnerabilities in the web-based management interface of Cisco Firepower Management Center (FMC) could allow an authenticated, remote attacker to conduct a stored cross-site scripting (XSS) attack against a user of the interface of an affected system. The vulnerabilities exist because the web-based management interface does not properly validate user-supplied input. An attacker could exploit these vulnerabilities by persuading a user of the interface to click a crafted link. A successful exploit could allow the attacker to execute arbitrary script code in the context of the affected interface or access sensitive, browser-based information.
Weakness: CWE-79
Which versions are affected by CVE-2021-1239?
It affects 1 product.
Products include Cisco Secure Firewall Management Center.
How do I fix CVE-2021-1239?
No fix has been published for CVE-2021-1239 yet. Limit exposure of the affected software until one is available.
Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.
Is CVE-2021-1239 being exploited?
There is no known exploitation of CVE-2021-1239 in the wild and no public exploit code.
Other vulnerabilities in Cisco Secure Firewall Management Center
- CVE-2026-20079 Cisco Firewall Management Center Authentication Bypass Using an Alternate Path or Channel
- CVE-2026-20131 Cisco Secure Firewall Management Center (FMC) Software and Cisco Security Cloud Control (SCC) Firewall Management Deserialization of Untrusted Data
- CVE-2026-20316 Cisco Secure Firewall Management Center Use of Hard-coded Password
- CVE-2025-20265 Cisco Secure Firewall Management Center Software Radius Remote Code Execution Vulnerability
- CVE-2024-20424 Command injection in Cisco Firepower Management Center
Sources
Also known as GHSA-hp68-5g22-cc6m.