U.S. CISA adds a Cisco IOS flaw to its Known Exploited Vulnerabilities catalog

Cisco IOS 12.4 contains multiple cross-site request forgery (CWE-352) flaws in the IOS HTTP management web interface that allow a remote attacker to execute arbitrary commands on the device. The flaws are triggered when an attacker induces an already-authenticated privileged (level 15) administrator's browser to send crafted HTTP requests to the router's web server, for example a "show privilege" command via the /level/15/exec/- URI or an "alias exec" configuration command via the /level/15/exec/-/configure/http URI, letting the attacker run commands with the administrator's privileges, potentially including device reconfiguration. Any Cisco IOS 12.4 device with the HTTP/HTTPS management server enabled and reachable from an administrator's browser is affected. CISA added the issue to the Known Exploited Vulnerabilities catalog on 2026-07-13, indicating known exploitation in the wild, and EPSS assigns a 33.9% probability of exploitation in the next 30 days (98th percentile); no public proof-of-concept is known and ransomware use is not confirmed.

Do: Inventory Cisco IOS devices for the 'ip http server' / 'ip http secure-server' configuration, and disable the HTTP/HTTPS management server where it is not needed or restrict it to management networks via access control lists. Apply Cisco's vendor-recommended fixed IOS release for CVE-2008-4128 in line with CISA BOD 26-04 deadlines, prioritizing internet-facing routers. Because exploitation is confirmed, also review device configurations and logs for unauthorized 'alias exec' entries or unexpected configuration changes.