CVE-2026-20309 Cisco Identity Services Engine Cross-Site Scripting Vulnerability
An unauthenticated attacker can execute arbitrary script code or access sensitive browser-based information by tricking a user into clicking a crafted link.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- None listed
What is CVE-2026-20309?
CVE-2026-20309 is a medium-severity cross-site scripting vulnerability in Cisco Identity Services Engine Software, published on 16 Sep 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official description
A vulnerability in the web-based management interface of Cisco Identity Services Engine (ISE) could allow an unauthenticated, remote attacker to conduct a reflected cross-site scripting (XSS) attack against a user of the interface. This vulnerability exists because the web-based management interface does not properly validate user-supplied input. An attacker could exploit this vulnerability 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-2026-20309?
How do I fix CVE-2026-20309?
No fix has been published for CVE-2026-20309 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-2026-20309 being exploited?
There is no known exploitation of CVE-2026-20309 in the wild and no public exploit code.
Sources
Also known as GHSA-48qc-vpgr-vrxg.