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

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

- **Severity:** High 8.1 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 24 Sep 2025
- **Updated:** 26 Feb 2026
- **Also known as:** GHSA-g4wr-69xr-36p6

## 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 (Improper Authentication)

## Which versions are affected by CVE-2025-20160?

It affects 2 products.


Products: 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.

## Is CVE-2025-20160 being exploited?

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

## Other vulnerabilities in Cisco Ios

- [CVE-2017-12240](https://insights.sbomify.com/CVE-2017-12240/): Cisco IOS and IOS XE Software DHCP Remote Code Execution (critical 9.8, exploited in the wild)
- [CVE-2017-3881](https://insights.sbomify.com/CVE-2017-3881/): Cisco IOS and IOS XE Remote Code Execution (critical 9.8, exploited in the wild)
- [CVE-2018-0167](https://insights.sbomify.com/CVE-2018-0167/): Cisco IOS, XR, and XE Software Buffer Overflow (high 8.8, exploited in the wild)
- [CVE-2017-6736](https://insights.sbomify.com/CVE-2017-6736/): Cisco IOS and IOS XE Software SNMP Remote Code Execution (high 8.8, exploited in the wild)
- [CVE-2017-6737](https://insights.sbomify.com/CVE-2017-6737/): Cisco IOS and IOS XE Software SNMP Remote Code Execution (high 8.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-20160 and fix it if it is affected.

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

Affected product: Cisco Ios. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2025-20160/ (Markdown: https://insights.sbomify.com/CVE-2025-20160/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-20160
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-20160
- OSV: https://osv.dev/vulnerability/CVE-2025-20160

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-20160/
Summaries are generated and may contain mistakes; the official description above is the record.