CVE-2026-20086 Denial of service in Cisco IOS XE Software
Unauthenticated remote attackers can cause denial of service on Cisco Catalyst CW9800 wireless controllers by sending malformed CAPWAP packets.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-20086?
CVE-2026-20086 is a high-severity denial of service vulnerability in Cisco IOS XE Software, published on 25 Mar 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
A vulnerability in the processing of Control and Provisioning of Wireless Access Points (CAPWAP) packets of Cisco IOS XE Wireless Controller Software for the Catalyst CW9800 Family could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. This vulnerability is due to improper handling of a malformed CAPWAP packet. An attacker could exploit this vulnerability by sending a malformed CAPWAP packet to an affected device. A successful exploit could allow the attacker to cause the affected device to reload unexpectedly, resulting in a DoS condition.
Weakness: CWE-230
Which versions are affected by CVE-2026-20086?
How do I fix CVE-2026-20086?
No fix has been published for CVE-2026-20086 yet. Limit exposure of the affected software until one is available.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-20086 being exploited?
There is no known exploitation of CVE-2026-20086 in the wild and no public exploit code.
Sources
Also known as GHSA-m53c-9wh4-q9hq.