Cisco Secure Firewall Management Center Software HTML Injection Vulnerability

TL;DR 📌

A high-severity HTML injection vulnerability has been identified in the Cisco Secure Firewall Management Center (FMC) Software. This flaw allows authenticated remote attackers to inject arbitrary HTML content into device-generated documents, potentially leading to sensitive information exposure. Cisco has released updates to address this issue, but there are no workarounds available.

What happened 🕵️‍♂️

A vulnerability in the web-based management interface of Cisco Secure Firewall Management Center Software could allow an authenticated, remote attacker to inject arbitrary HTML content into a device-generated document. This vulnerability arises from improper validation of user-supplied data. An attacker with valid credentials (at least Security Analyst role) could exploit this vulnerability to alter document layouts, read arbitrary files from the underlying operating system, and conduct server-side request forgery (SSRF) attacks.

Affected products 🖥️

The vulnerability affects the Cisco Secure FMC Software, regardless of device configuration. Other products, such as Secure Firewall Adaptive Security Appliance (ASA) Software and Secure Firewall Threat Defense (FTD) Software, are confirmed not to be vulnerable.

Fixed software 🔧

Upgrade to the first fixed release in your train (or later):

Workarounds 🧯

There are no workarounds that address this vulnerability.

Risk in context 🎯

The vulnerability has a CVSS score of 8.5, indicating a high severity risk. Exploitation requires valid user credentials, but successful attacks could lead to significant data exposure and manipulation. Given the nature of the vulnerability, it is crucial for affected organizations to prioritize patching.

Fast facts ⚡

• Vulnerability: HTML Injection
• CVSS Score: 8.5 (High)
• Exploitation: Requires valid credentials
• Impact: Potential data exposure and manipulation
• Workarounds: None available

For leadership 🧭

Executive summary. Cisco’s Secure Firewall Management Center has a flaw that lets someone with only low-privilege analyst credentials manipulate generated documents to pull files from the underlying server and reach internal systems via SSRF. There is no workaround, so this needs patching as part of the next available change window rather than being deferred.

Why it matters:

• The attack path requires only a Security Analyst account, one of the lowest-privilege roles in FMC, not administrative access.
• Successful exploitation lets an attacker read arbitrary files from the FMC appliance’s underlying operating system, not just tamper with a report’s appearance.
• The same flaw enables server-side request forgery, meaning the FMC server itself can be made to issue requests into other parts of the network it can reach.
• With a CVSS score of 8.5 and no vendor-supplied workaround, mitigation options until patching are limited.

Now / Next / Later:

• Now: Review who currently holds Security Analyst or higher roles on your Secure Firewall Management Center and confirm those accounts are still needed and properly controlled.
• Next: Upgrade affected FMC appliances to the first fixed release identified for your software train in the next scheduled change window, since no interim workaround exists.
• Later: Build FMC patch tracking into routine firewall management maintenance and periodically audit role assignments so low-privilege accounts are not left with more access than their job requires.