Vulnerability Database

393,392

Total vulnerabilities in the database

CVE-2025-20160 — cisco / ios

Improper Authentication

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.

  • Published: Sep 24, 2025
  • Updated: Oct 3, 2026
  • CVE: CVE-2025-20160
  • Severity: High
  • Exploit:
  • CISA KEV:

CVSS v3:

  • Severity: High
  • Score: 8.1
  • AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
Software Affected versions
cisco / ios = 15.2(4)e6
cisco / ios = 15.2(4)e7
cisco / ios = 15.2(4)e8
cisco / ios = 15.2(4)e9
cisco / ios = 15.2(4)e10
cisco / ios = 15.2(4)e10a
cisco / ios = 15.2(4)e10d
cisco / ios = 15.2(6)e1
cisco / ios = 15.2(6)e2
cisco / ios = 15.2(6)e2a
cisco / ios = 15.2(6)e2b
cisco / ios = 15.2(6)e3
cisco / ios = 15.2(6)eb
cisco / ios = 15.2(7)e
cisco / ios = 15.2(7)e0a
cisco / ios = 15.2(7)e0b
cisco / ios = 15.2(7)e0s
cisco / ios = 15.2(7)e1
cisco / ios = 15.2(7)e1a
cisco / ios = 15.2(7)e2
cisco / ios = 15.2(7)e2a
cisco / ios = 15.2(7)e3
cisco / ios = 15.2(7)e3k
cisco / ios = 15.2(7)e4
cisco / ios = 15.2(7)e5
cisco / ios = 15.2(7)e6
cisco / ios = 15.2(7)e7
cisco / ios = 15.2(7)e8
cisco / ios = 15.2(7)e9
cisco / ios = 15.2(7)e10
cisco / ios = 15.2(7)e11
cisco / ios = 15.2(7)e12
cisco / ios = 15.2(7a)e0b
cisco / ios = 15.2(7b)e0b
cisco / ios = 15.2(8)e
cisco / ios = 15.2(8)e1
cisco / ios = 15.2(8)e2
cisco / ios = 15.2(8)e3
cisco / ios = 15.2(8)e4
cisco / ios = 15.2(8)e5
cisco / ios = 15.2(8)e6
cisco / ios = 15.2(8)e7
cisco / ios = 15.5(1)sy2
cisco / ios = 15.5(1)sy3
cisco / ios = 15.5(1)sy4
cisco / ios = 15.5(1)sy5
cisco / ios = 15.5(1)sy6
cisco / ios = 15.5(1)sy7
cisco / ios = 15.5(1)sy8
cisco / ios = 15.5(1)sy9
cisco / ios = 15.5(1)sy10
cisco / ios = 15.5(1)sy11
cisco / ios = 15.5(1)sy12
cisco / ios = 15.5(1)sy13
cisco / ios = 15.5(1)sy14
cisco / ios = 15.5(1)sy15
cisco / ios = 15.5(3)m7
cisco / ios = 15.5(3)m8
cisco / ios = 15.5(3)m9
cisco / ios = 15.5(3)m10
cisco / ios = 15.5(3)s8
cisco / ios = 15.5(3)s9
cisco / ios = 15.5(3)s9a
cisco / ios = 15.5(3)s10
cisco / ios = 15.6(2)sp5
cisco / ios = 15.6(2)sp6
cisco / ios = 15.6(2)sp7
cisco / ios = 15.6(2)sp8
cisco / ios = 15.6(2)sp9
cisco / ios = 15.6(3)m4
cisco / ios = 15.6(3)m5
cisco / ios = 15.6(3)m6
cisco / ios = 15.6(3)m6a
cisco / ios = 15.6(3)m6b
cisco / ios = 15.6(3)m7
cisco / ios = 15.6(3)m8
cisco / ios = 15.6(3)m9
cisco / ios = 15.7(3)m2
cisco / ios = 15.7(3)m3
cisco / ios = 15.7(3)m4
cisco / ios = 15.7(3)m4a
cisco / ios = 15.7(3)m4b
cisco / ios = 15.7(3)m5
cisco / ios = 15.7(3)m6
cisco / ios = 15.7(3)m7
cisco / ios = 15.7(3)m8
cisco / ios = 15.7(3)m9
cisco / ios = 15.8(3)m
cisco / ios = 15.8(3)m0a
cisco / ios = 15.8(3)m0b
cisco / ios = 15.8(3)m1
cisco / ios = 15.8(3)m1a
cisco / ios = 15.8(3)m2
cisco / ios = 15.8(3)m2a
cisco / ios = 15.8(3)m3
cisco / ios = 15.8(3)m3a
cisco / ios = 15.8(3)m3b
cisco / ios = 15.8(3)m4
cisco / ios = 15.8(3)m5
cisco / ios = 15.8(3)m6
cisco / ios = 15.8(3)m7
cisco / ios = 15.8(3)m8
cisco / ios = 15.8(3)m9
cisco / ios = 15.9(3)m
cisco / ios = 15.9(3)m0a
cisco / ios = 15.9(3)m1
cisco / ios = 15.9(3)m2
cisco / ios = 15.9(3)m2a
cisco / ios = 15.9(3)m3
cisco / ios = 15.9(3)m3a
cisco / ios = 15.9(3)m3b
cisco / ios = 15.9(3)m4
cisco / ios = 15.9(3)m4a
cisco / ios = 15.9(3)m5
cisco / ios = 15.9(3)m6
cisco / ios = 15.9(3)m6a
cisco / ios = 15.9(3)m6b
cisco / ios = 15.9(3)m7
cisco / ios = 15.9(3)m7a
cisco / ios = 15.9(3)m8
cisco / ios = 15.9(3)m8b
cisco / ios = 15.9(3)m9
cisco / ios = 15.9(3)m10
cisco / ios = 15.9(3)m11
cisco / ios_xe = 3.8.6e
cisco / ios_xe = 3.8.7e
cisco / ios_xe = 3.8.8e
cisco / ios_xe = 3.8.9e
cisco / ios_xe = 3.8.10e
cisco / ios_xe = 3.10.1e
cisco / ios_xe = 3.10.2e
cisco / ios_xe = 3.10.3e
cisco / ios_xe = 3.11.0e
cisco / ios_xe = 3.11.1ae
cisco / ios_xe = 3.11.1e
cisco / ios_xe = 3.11.2e
cisco / ios_xe = 3.11.3ae
cisco / ios_xe = 3.11.3e
cisco / ios_xe = 3.11.4e
cisco / ios_xe = 3.11.5e
cisco / ios_xe = 3.11.6e
cisco / ios_xe = 3.11.7e
cisco / ios_xe = 3.11.8e
cisco / ios_xe = 3.11.9e
cisco / ios_xe = 3.11.10e
cisco / ios_xe = 3.11.11e
cisco / ios_xe = 3.11.12e
cisco / ios_xe = 3.16.8s
cisco / ios_xe = 3.16.9s
cisco / ios_xe = 3.16.10s
cisco / ios_xe = 3.18.5sp
cisco / ios_xe = 3.18.6sp
cisco / ios_xe = 3.18.7sp
cisco / ios_xe = 3.18.8asp
cisco / ios_xe = 3.18.9sp
cisco / ios_xe = 16.6.5
cisco / ios_xe = 16.6.5a
cisco / ios_xe = 16.6.6
cisco / ios_xe = 16.6.7
cisco / ios_xe = 16.6.8
cisco / ios_xe = 16.6.9
cisco / ios_xe = 16.6.10
cisco / ios_xe = 16.8.1
cisco / ios_xe = 16.8.1a
cisco / ios_xe = 16.8.1b
cisco / ios_xe = 16.8.1c
cisco / ios_xe = 16.8.1d
cisco / ios_xe = 16.8.1e
cisco / ios_xe = 16.8.1s
cisco / ios_xe = 16.8.2
cisco / ios_xe = 16.8.3
cisco / ios_xe = 16.9.1
cisco / ios_xe = 16.9.1a
cisco / ios_xe = 16.9.1b
cisco / ios_xe = 16.9.1s
cisco / ios_xe = 16.9.2
cisco / ios_xe = 16.9.3
cisco / ios_xe = 16.9.3a
cisco / ios_xe = 16.9.4
cisco / ios_xe = 16.9.5
cisco / ios_xe = 16.9.5f
cisco / ios_xe = 16.9.6
cisco / ios_xe = 16.9.7
cisco / ios_xe = 16.9.8
cisco / ios_xe = 16.10.1
cisco / ios_xe = 16.10.1a
cisco / ios_xe = 16.10.1b
cisco / ios_xe = 16.10.1c
cisco / ios_xe = 16.10.1d
cisco / ios_xe = 16.10.1e
cisco / ios_xe = 16.10.1f
cisco / ios_xe = 16.10.1g
cisco / ios_xe = 16.10.1s
cisco / ios_xe = 16.10.2
cisco / ios_xe = 16.10.3
cisco / ios_xe = 16.11.1
cisco / ios_xe = 16.11.1a
cisco / ios_xe = 16.11.1b
cisco / ios_xe = 16.11.1s
cisco / ios_xe = 16.11.2
cisco / ios_xe = 16.12.1
cisco / ios_xe = 16.12.1a
cisco / ios_xe = 16.12.1c
cisco / ios_xe = 16.12.1s
cisco / ios_xe = 16.12.1t
cisco / ios_xe = 16.12.1w
cisco / ios_xe = 16.12.1x
cisco / ios_xe = 16.12.1y
cisco / ios_xe = 16.12.1z1
cisco / ios_xe = 16.12.1z2
cisco / ios_xe = 16.12.2
cisco / ios_xe = 16.12.2a
cisco / ios_xe = 16.12.2s
cisco / ios_xe = 16.12.3
cisco / ios_xe = 16.12.3a
cisco / ios_xe = 16.12.3s
cisco / ios_xe = 16.12.4
cisco / ios_xe = 16.12.4a
cisco / ios_xe = 16.12.5
cisco / ios_xe = 16.12.5a
cisco / ios_xe = 16.12.5b
cisco / ios_xe = 16.12.6
cisco / ios_xe = 16.12.6a
cisco / ios_xe = 16.12.7
cisco / ios_xe = 16.12.8
cisco / ios_xe = 16.12.9
cisco / ios_xe = 16.12.10
cisco / ios_xe = 16.12.10a
cisco / ios_xe = 16.12.11
cisco / ios_xe = 16.12.12
cisco / ios_xe = 16.12.13
cisco / ios_xe = 17.1.1
cisco / ios_xe = 17.1.1a
cisco / ios_xe = 17.1.1s
cisco / ios_xe = 17.1.1t
cisco / ios_xe = 17.1.3
cisco / ios_xe = 17.2.1
cisco / ios_xe = 17.2.1a
cisco / ios_xe = 17.2.1r
cisco / ios_xe = 17.2.1v
cisco / ios_xe = 17.2.2
cisco / ios_xe = 17.2.3
cisco / ios_xe = 17.3.1
cisco / ios_xe = 17.3.1a
cisco / ios_xe = 17.3.1w
cisco / ios_xe = 17.3.1x
cisco / ios_xe = 17.3.1z
cisco / ios_xe = 17.3.2
cisco / ios_xe = 17.3.2a
cisco / ios_xe = 17.3.3
cisco / ios_xe = 17.3.4
cisco / ios_xe = 17.3.4a
cisco / ios_xe = 17.3.4b
cisco / ios_xe = 17.3.4c
cisco / ios_xe = 17.3.5
cisco / ios_xe = 17.3.5a
cisco / ios_xe = 17.3.5b
cisco / ios_xe = 17.3.6
cisco / ios_xe = 17.3.7
cisco / ios_xe = 17.3.8
cisco / ios_xe = 17.3.8a
cisco / ios_xe = 17.4.1
cisco / ios_xe = 17.4.1a
cisco / ios_xe = 17.4.1b
cisco / ios_xe = 17.4.2
cisco / ios_xe = 17.4.2a
cisco / ios_xe = 17.5.1
cisco / ios_xe = 17.5.1a
cisco / ios_xe = 17.6.1
cisco / ios_xe = 17.6.1a
cisco / ios_xe = 17.6.1w
cisco / ios_xe = 17.6.1x
cisco / ios_xe = 17.6.1y
cisco / ios_xe = 17.6.1z
cisco / ios_xe = 17.6.1z1
cisco / ios_xe = 17.6.2
cisco / ios_xe = 17.6.3
cisco / ios_xe = 17.6.3a
cisco / ios_xe = 17.6.4
cisco / ios_xe = 17.6.5
cisco / ios_xe = 17.6.5a
cisco / ios_xe = 17.6.6
cisco / ios_xe = 17.6.6a
cisco / ios_xe = 17.6.7
cisco / ios_xe = 17.6.8
cisco / ios_xe = 17.6.8a
cisco / ios_xe = 17.7.1
cisco / ios_xe = 17.7.1a
cisco / ios_xe = 17.7.1b
cisco / ios_xe = 17.7.2
cisco / ios_xe = 17.8.1
cisco / ios_xe = 17.8.1a
cisco / ios_xe = 17.9.1
cisco / ios_xe = 17.9.1a
cisco / ios_xe = 17.9.1w
cisco / ios_xe = 17.9.1x
cisco / ios_xe = 17.9.1x1
cisco / ios_xe = 17.9.1y
cisco / ios_xe = 17.9.1y1
cisco / ios_xe = 17.9.2
cisco / ios_xe = 17.9.2a
cisco / ios_xe = 17.9.3
cisco / ios_xe = 17.9.3a
cisco / ios_xe = 17.9.4
cisco / ios_xe = 17.9.4a
cisco / ios_xe = 17.9.5
cisco / ios_xe = 17.9.5a
cisco / ios_xe = 17.9.5b
cisco / ios_xe = 17.9.5e
cisco / ios_xe = 17.9.5f
cisco / ios_xe = 17.9.6
cisco / ios_xe = 17.9.6a
cisco / ios_xe = 17.9.7
cisco / ios_xe = 17.9.7a
cisco / ios_xe = 17.9.7b
cisco / ios_xe = 17.10.1
cisco / ios_xe = 17.10.1a
cisco / ios_xe = 17.10.1b
cisco / ios_xe = 17.11.1
cisco / ios_xe = 17.11.1a
cisco / ios_xe = 17.11.99sw
cisco / ios_xe = 17.12.1
cisco / ios_xe = 17.12.1a
cisco / ios_xe = 17.12.1w
cisco / ios_xe = 17.12.1x
cisco / ios_xe = 17.12.1y
cisco / ios_xe = 17.12.1z
cisco / ios_xe = 17.12.1z1
cisco / ios_xe = 17.12.1z2
cisco / ios_xe = 17.12.1z3
cisco / ios_xe = 17.12.1z4
cisco / ios_xe = 17.12.2
cisco / ios_xe = 17.12.2a
cisco / ios_xe = 17.12.3
cisco / ios_xe = 17.12.3a
cisco / ios_xe = 17.12.4
cisco / ios_xe = 17.12.4a
cisco / ios_xe = 17.12.4b
cisco / ios_xe = 17.12.5
cisco / ios_xe = 17.12.5a
cisco / ios_xe = 17.12.5b
cisco / ios_xe = 17.12.5c
cisco / ios_xe = 17.13.1
cisco / ios_xe = 17.13.1a
cisco / ios_xe = 17.14.1
cisco / ios_xe = 17.14.1a
cisco / ios_xe = 17.15.1
cisco / ios_xe = 17.15.1a
cisco / ios_xe = 17.15.1b
cisco / ios_xe = 17.15.1w
cisco / ios_xe = 17.15.1x
cisco / ios_xe = 17.15.1y
cisco / ios_xe = 17.15.2
cisco / ios_xe = 17.15.2a
cisco / ios_xe = 17.15.2b
cisco / ios_xe = 17.15.2c
cisco / ios_xe = 17.15.3
cisco / ios_xe = 17.15.3a
cisco / ios_xe = 17.15.3b

Frequently Asked Questions

A security vulnerability is a weakness in software, hardware, or configuration that can be exploited to compromise confidentiality, integrity, or availability. Many vulnerabilities are tracked as CVEs (Common Vulnerabilities and Exposures), which provide a standardized identifier so teams can coordinate patching, mitigation, and risk assessment across tools and vendors.

CVSS (Common Vulnerability Scoring System) estimates technical severity, but it doesn't automatically equal business risk. Prioritize using context like internet exposure, affected asset criticality, known exploitation (proof-of-concept or in-the-wild), and whether compensating controls exist. A "Medium" CVSS on an exposed, production system can be more urgent than a "Critical" on an isolated, non-production host.

A vulnerability is the underlying weakness. An exploit is the method or code used to take advantage of it. A zero-day is a vulnerability that is unknown to the vendor or has no publicly available fix when attackers begin using it. In practice, risk increases sharply when exploitation becomes reliable or widespread.

Recurring findings usually come from incomplete Asset Discovery, inconsistent patch management, inherited images, and configuration drift. In modern environments, you also need to watch the software supply chain: dependencies, containers, build pipelines, and third-party services can reintroduce the same weakness even after you patch a single host. Unknown or unmanaged assets (often called Shadow IT) are a common reason the same issues resurface.

Use a simple, repeatable triage model: focus first on externally exposed assets, high-value systems (identity, VPN, email, production), vulnerabilities with known exploits, and issues that enable remote code execution or privilege escalation. Then enforce patch SLAs and track progress using consistent metrics so remediation is steady, not reactive.

SynScan combines attack surface monitoring and continuous security auditing to keep your inventory current, flag high-impact vulnerabilities early, and help you turn raw findings into a practical remediation plan.