CVE-2025-20160 Auth bypass in Cisco IOS XE Software

High 8.1 Published 24 Sep 2025 Updated 26 Feb 2026

An unauthenticated remote attacker can bypass authentication or view sensitive data via TACACS+ if the shared secret is not configured.

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-2025-20160?

CVE-2025-20160 is a high-severity authentication bypass vulnerability in Cisco Ios, published on 24 Sep 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official 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

Which versions are affected by CVE-2025-20160?

It affects 2 products.

Products include Cisco Ios, Cisco Ios Xe.

How do I fix CVE-2025-20160?

No fix has been published for CVE-2025-20160 yet. Limit exposure of the affected software until one is available.

Upgrade, and rotate credentials and sessions that may have been exposed. More about Authentication bypass.

Is CVE-2025-20160 being exploited?

There is no known exploitation of CVE-2025-20160 in the wild and no public exploit code.

All Cisco Ios vulnerabilities

Sources

Also known as GHSA-g4wr-69xr-36p6.