Improper Handling of Syntactically Invalid Structure in Cisco IOS XE - CVE-2026-20125
Published: March 25, 2026
Vulnerability identifier: #VU124587
CSH Severity: Medium
CVSS v4: 7.1 [CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-20125
CWE-ID: CWE-228
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote user to cause a denial of service.
The vulnerability exists due to improper validation of user-supplied input in the HTTP Server feature when handling HTTP requests. A remote user can send malformed HTTP requests to an affected device to cause a watchdog timer to expire and the device to reload, resulting in a denial of service.
To exploit this vulnerability, the attacker must have a valid user account.
Affected software
Cisco IOS XE
How to mitigate CVE-2026-20125
Install security update from vendor's website.
Cisco IOS XE - update to 17.15.5