Cisco IOS: request forgery flaw under attack

What is affected

Cisco IOS is found on ordinary personal computers and phones, so this is not only a problem for companies. If you use it and have not updated since the fix was released, you are exposed.

Cisco IOS 12.4 contains multiple cross-site forgery vulnerabilities that allows remote attackers to execute arbitrary commands via (1) a certain "show privilege" command to the /level/15/exec/- URI, and (2) a certain "alias exec" command to the /level/15/exec/-/configure/http URI.

What an attacker can do

This is a request forgery flaw. It lets an attacker trick a logged-in user's browser into performing actions the user never intended, such as changing settings or creating accounts.

How it is reached

Over the internet or network

Access the attacker needs

No account needed

Does the victim have to do something?

Yes, the victim must open or click something

What to do

1. Update Cisco IOS now. Open the update or "About" screen, install whatever is offered and restart the app or device, because the fix is not active until you do.
2. Turn on automatic updates so the next fix arrives without you having to look for it.
3. If your device is too old to receive this update, stop using the affected app for anything sensitive and plan a replacement.

Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.

Vendor advisories and fixes

• cisco.comwww.cisco.com/c/en/us/obsolete/ios-nx-os-software/cisco-ios-software-releases-12-4-mainlin

How urgent is it

CISA added this vulnerability to its Known Exploited Vulnerabilities catalogue on July 13, 2026, which means there is reliable evidence of attacks in the wild. US federal agencies must fix it by July 16, 2026, a deadline that has already passed. That deadline does not bind anyone else, but it shows how seriously the agency rates it.

The EPSS model estimates a 34% probability that this flaw will be exploited somewhere in the next 30 days. That is higher than 98% of all scored vulnerabilities.

Its CVSS severity score is 8.1 out of 10 (high), as recorded in the US National Vulnerability Database.

Technical description

Multiple cross-site request forgery (CSRF) vulnerabilities in the HTTP Administration component in Cisco IOS 12.4 on the 871 Integrated Services Router allow remote attackers to execute arbitrary commands via (1) a certain "show privilege" command to the /level/15/exec/- URI, and (2) a certain "alias exec" command to the /level/15/exec/-/configure/http URI. NOTE: some of these details are obtained from third party information.