CVE-2024-20256 Cross-site scripting in Cisco Secure Email and Web Manager
An authenticated attacker can execute arbitrary script code or access sensitive browser information via a crafted link in the Cisco Secure Email and Web Manager interface.
- 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-2024-20256?
CVE-2024-20256 is a medium-severity cross-site scripting vulnerability in Cisco Asyncos, published on 15 May 2024. An attacker needs administrator access to exploit it, and only if a user opens a file or follows a link.
Official description
A vulnerability in the web-based management interface of Cisco AsyncOS Software for Cisco Secure Email and Web Manager and Secure Web Appliance could allow an authenticated, remote attacker to conduct an XSS attack against a user of the interface. This vulnerability is due to insufficient validation of user input. An attacker could exploit this vulnerability by persuading a user of an affected 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-2024-20256?
It affects 4 products.
Products include Cisco Asyncos, Cisco Secure Email and Web Manager Virtual Appliance M100v, Cisco Secure Email and Web Manager Virtual Appliance M300v, Cisco Secure Email and Web Manager Virtual Appliance M600v.
How do I fix CVE-2024-20256?
No fix has been published for CVE-2024-20256 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-2024-20256 being exploited?
There is no known exploitation of CVE-2024-20256 in the wild and no public exploit code.
Other vulnerabilities in Cisco Asyncos
- CVE-2025-20393 Cisco Multiple Products Improper Input Validation
- CVE-2026-76519 Cisco Secure Email Gateway Relative Path Traversal
- CVE-2026-76461 Cisco Secure Email Gateway SQL Injection
- CVE-2024-20435 Command injection in Cisco Secure Web Appliance
- CVE-2019-15956 Cisco Web Security Appliance Unauthorized Device Reset Vulnerability
Sources
Also known as GHSA-26f5-24g6-27vm.