Cisco IOS XE Web UI Command Injection Vulnerability

Cisco IOS XE contains a command injection vulnerability in the web user interface. When chained with CVE-2023-20198, the attacker can leverage the new local user to elevate privilege to root and write the implant to the file system. Cisco identified CVE-2023-20273 as the vulnerability exploited to deploy the implant. CVE-2021-1435, previously associated with the exploitation events, is no longer believed to be related to this activity.

Published 4 Sep 2026Updated 4 Sep 20264 sources
CVSS 10.0 PoC CANDIDATE△ CISA KEV

What happened

Cisco IOS XE contains a command injection vulnerability in the web user interface. When chained with CVE-2023-20198, the attacker can leverage the new local user to elevate privilege to root and write the implant to the file system. Cisco identified CVE-2023-20273 as the vulnerability exploited to deploy the implant. CVE-2021-1435, previously associated with the exploitation events, is no longer believed to be related to this activity.

Affected versions

Cisco IOS XE Web UI: See original advisory Fixed: See vendor advisory.

Why it matters

This source correlation may provide earlier visibility while structured CVE metadata is still being updated.

Detection & mitigation

  • Review the original advisory and validate affected versions.
  • Apply vendor-provided updates or mitigations when available.

Public PoC references