CVE-2025-20160
A vulnerability in the implementation of the TACACS+ protocol in Cisco IOS Software and Cisco IOS XE Software could allow an unauthenticated, remote attacker to view sensitive data or bypass authentic
Description
A vulnerability in the implementation of the TACACS+ protocol in Cisco IOS Software and Cisco IOS XE Software could allow an unauthenticated, remote attacker to view sensitive data or bypass authentication. This vulnerability exists because the system does not properly check whether the required TACACS+ shared secret is configured. A machine-in-the-middle attacker could exploit this vulnerability by intercepting and reading unencrypted TACACS+ messages or impersonating the TACACS+ server and falsely accepting arbitrary authentication requests. A successful exploit could allow the attacker to view sensitive information in a TACACS+ message or bypass authentication and gain access to the affected device.
Weakness: CWE-287
Affected products
| Vendor | Product | Category | Matched by |
|---|---|---|---|
| Cisco | Cisco IOS Software | Routing & Switching | cna-assigner |
| Cisco | Cisco IOS XE Software | Routing & Switching | cna-assigner |
Vendor-reported products (2)
- Cisco · IOS
- Cisco · Cisco IOS XE Software
Vendor advisory
Cisco IOS and IOS XE Software TACACS+ Authentication Bypass Vulnerability
Cisco’s rating: High (advisory CVSS 8.1) · Published Sep 24, 2025 · updated Oct 1, 2025 (revision 1.1)
Bug ID: CSCwm99306
The vendor’s rating applies to the whole advisory and can differ from this CVE’s own CVSS severity. Where this comes from