SB2026080631 - Denial of service in Cisco IOS XE web-based management interface

Description

This security bulletin contains information about 1 vulnerability.

1) Buffer over-read (CVE-ID: CVE-2026-20311)

CWE-ID: CWE-126 - Buffer over-read

CVSSv4: 6 [CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]

The vulnerability allows a remote user to cause a denial of service.

The vulnerability exists due to insufficient error handling in the web-based management interface when authenticating with a malformed certificate. A remote user can authenticate with a malformed certificate to cause a denial of service.

Only devices with the HTTP Server feature and PIV-based authentication enabled are vulnerable. A successful exploit causes the affected device to reload.

Remediation

Install update from vendor's website.

References

• https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-xe-webui-dos-PtAODAWW
• https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-xe-webui-dos-PtAODAWW
• https://bst.cloudapps.cisco.com/bugsearch/bug/CSCwu25287