Medium [CVE-2026-20110] Cisco IOS XE Software Denial of Service Vulnerability
This medium-severity Cisco advisory covers CVE-2026-20110 affecting IOS XE Software.
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Summary
A vulnerability in the CLI of Cisco IOS XE Software could allow an authenticated, local attacker to cause a denial of service (DoS) condition on an affected device. This vulnerability exists because incorrect privileges are associated with the start maintenance command.
An attacker could exploit this vulnerability by accessing the management CLI of the affected device as a low-privileged user and using the start maintenance command. A successful exploit could allow the attacker to put the device in maintenance mode, which shuts down interfaces, resulting in a denial of service (DoS) condition.
In case of exploitation, a device administrator can connect to the CLI and use the stop maintenance command to restore operations. Cisco has released software updates that address this vulnerability.
There are workarounds that address this vulnerability. This advisory is part of the March 2026 release of the Cisco IOS and IOS XE Software Security Advisory Bundled Publication.
- Scope: At the time of publication, this vulnerability affected Cisco IOS XE Software if it supported the start maintenance command.
Official advisory · high-confidence parse· fetched 2 months ago·verify at source
Fixed versions
No fixed release is recorded yet. That does not prove no patch exists — confirm against the vendor advisory.
Official advisory · high-confidence parse· fetched 2 months ago·verify at source
Mitigation checklist
- There is a workaround that addresses this vulnerability. Set the privilege level of the start maintenance command manually by connecting to the device management CLI and using the privilege exec level 15 start maintenance configuration command, as shown in the following example:
- Router# configuration terminal
- Enter configuration commands, one per line. End with CNTL/Z.
- Router(config)# privilege exec level 15 start maintenance
- While this workaround has been deployed and was proven successful in a test environment, customers should determine the applicability and effectiveness in their own environment and under their own use conditions. Customers should be aware that any workaround or mitigation that is implemented may negatively impact the functionality or performance of their network based on intrinsic customer depl…
Official advisory · high-confidence parse· fetched 2 months ago·verify at source
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