Vulnerability Database

393,544

Total vulnerabilities in the database

CVE-2020-3226 — cisco / ios

Improper Input Validation

A vulnerability in the Session Initiation Protocol (SIP) library of Cisco IOS Software and Cisco IOS XE Software could allow an unauthenticated, remote attacker to trigger a reload of an affected device, resulting in a denial of service (DoS) condition. The vulnerability is due to insufficient sanity checks on received SIP messages. An attacker could exploit this vulnerability by sending crafted SIP messages to an affected device. A successful exploit could allow the attacker to cause the affected device to reload, resulting in a denial of service condition.

  • Published: Jun 3, 2020
  • Updated: Oct 4, 2026
  • CVE: CVE-2020-3226
  • Severity: High
  • Exploit:
  • CISA KEV:

CVSS v3:

  • Severity: High
  • Score: 8.6
  • AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H

CVSS v2:

  • Severity: High
  • Score: 7.8
  • AV:N/AC:L/Au:N/C:N/I:N/A:C

CWEs:

Software Affected versions
cisco / ios = 15.0(2)sg11a
cisco / ios = 15.3(3)jaa1
cisco / ios = 15.3(3)jpi
cisco / ios = 15.3(3)jpj
cisco / ios = 15.3(3)m
cisco / ios = 15.3(3)m1
cisco / ios = 15.3(3)m2
cisco / ios = 15.3(3)m3
cisco / ios = 15.3(3)m4
cisco / ios = 15.3(3)m5
cisco / ios = 15.3(3)m6
cisco / ios = 15.3(3)m7
cisco / ios = 15.3(3)m8
cisco / ios = 15.3(3)m8a
cisco / ios = 15.3(3)m9
cisco / ios = 15.3(3)m10
cisco / ios = 15.3(3)xb12
cisco / ios = 15.4(1)cg
cisco / ios = 15.4(1)t
cisco / ios = 15.4(1)t1
cisco / ios = 15.4(1)t2
cisco / ios = 15.4(1)t3
cisco / ios = 15.4(1)t4
cisco / ios = 15.4(2)cg
cisco / ios = 15.4(2)t
cisco / ios = 15.4(2)t1
cisco / ios = 15.4(2)t2
cisco / ios = 15.4(2)t3
cisco / ios = 15.4(2)t4
cisco / ios = 15.4(3)m
cisco / ios = 15.4(3)m1
cisco / ios = 15.4(3)m2
cisco / ios = 15.4(3)m3
cisco / ios = 15.4(3)m4
cisco / ios = 15.4(3)m5
cisco / ios = 15.4(3)m6
cisco / ios = 15.4(3)m6a
cisco / ios = 15.4(3)m7
cisco / ios = 15.4(3)m7a
cisco / ios = 15.4(3)m8
cisco / ios = 15.4(3)m9
cisco / ios = 15.4(3)m10
cisco / ios = 15.5(1)t
cisco / ios = 15.5(1)t1
cisco / ios = 15.5(1)t2
cisco / ios = 15.5(1)t3
cisco / ios = 15.5(1)t4
cisco / ios = 15.5(2)t
cisco / ios = 15.5(2)t1
cisco / ios = 15.5(2)t2
cisco / ios = 15.5(2)t3
cisco / ios = 15.5(2)t4
cisco / ios = 15.5(2)xb
cisco / ios = 15.5(3)m
cisco / ios = 15.5(3)m1
cisco / ios = 15.5(3)m2
cisco / ios = 15.5(3)m2a
cisco / ios = 15.5(3)m3
cisco / ios = 15.5(3)m4
cisco / ios = 15.5(3)m4a
cisco / ios = 15.5(3)m4b
cisco / ios = 15.5(3)m4c
cisco / ios = 15.5(3)m5
cisco / ios = 15.5(3)m6
cisco / ios = 15.5(3)m6a
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 = 15.6(1)t
cisco / ios = 15.6(1)t0a
cisco / ios = 15.6(1)t1
cisco / ios = 15.6(1)t2
cisco / ios = 15.6(1)t3
cisco / ios = 15.6(2)t
cisco / ios = 15.6(2)t1
cisco / ios = 15.6(2)t2
cisco / ios = 15.6(2)t3
cisco / ios = 15.6(3)m
cisco / ios = 15.6(3)m0a
cisco / ios = 15.6(3)m1
cisco / ios = 15.6(3)m1a
cisco / ios = 15.6(3)m1b
cisco / ios = 15.6(3)m2
cisco / ios = 15.6(3)m2a
cisco / ios = 15.6(3)m3
cisco / ios = 15.6(3)m3a
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)m7
cisco / ios = 15.7(3)m
cisco / ios = 15.7(3)m1
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 = 15.8(3)m
cisco / ios = 15.8(3)m0a
cisco / ios = 15.8(3)m1
cisco / ios = 15.8(3)m2
cisco / ios_xe = 3.10.0s
cisco / ios_xe = 3.10.1s
cisco / ios_xe = 3.10.2as
cisco / ios_xe = 3.10.2s
cisco / ios_xe = 3.10.2ts
cisco / ios_xe = 3.10.3s
cisco / ios_xe = 3.10.4s
cisco / ios_xe = 3.10.5s
cisco / ios_xe = 3.10.6s
cisco / ios_xe = 3.10.7s
cisco / ios_xe = 3.10.8as
cisco / ios_xe = 3.10.8s
cisco / ios_xe = 3.10.9s
cisco / ios_xe = 3.10.10s
cisco / ios_xe = 3.11.0s
cisco / ios_xe = 3.11.1s
cisco / ios_xe = 3.11.2s
cisco / ios_xe = 3.11.3s
cisco / ios_xe = 3.11.4s
cisco / ios_xe = 3.12.0as
cisco / ios_xe = 3.12.0s
cisco / ios_xe = 3.12.1s
cisco / ios_xe = 3.12.2s
cisco / ios_xe = 3.12.3s
cisco / ios_xe = 3.12.4s
cisco / ios_xe = 3.13.0s
cisco / ios_xe = 3.13.1s
cisco / ios_xe = 3.13.2as
cisco / ios_xe = 3.13.2s
cisco / ios_xe = 3.13.3s
cisco / ios_xe = 3.13.4s
cisco / ios_xe = 3.13.5as
cisco / ios_xe = 3.13.5s
cisco / ios_xe = 3.13.6as
cisco / ios_xe = 3.13.6bs
cisco / ios_xe = 3.13.6s
cisco / ios_xe = 3.13.7as
cisco / ios_xe = 3.13.7s
cisco / ios_xe = 3.13.8s
cisco / ios_xe = 3.13.9s
cisco / ios_xe = 3.13.10s
cisco / ios_xe = 3.14.0s
cisco / ios_xe = 3.14.1s
cisco / ios_xe = 3.14.2s
cisco / ios_xe = 3.14.3s
cisco / ios_xe = 3.14.4s
cisco / ios_xe = 3.15.0s
cisco / ios_xe = 3.15.1cs
cisco / ios_xe = 3.15.1s
cisco / ios_xe = 3.15.2s
cisco / ios_xe = 3.15.3s
cisco / ios_xe = 3.15.4s
cisco / ios_xe = 3.16.0cs
cisco / ios_xe = 3.16.0s
cisco / ios_xe = 3.16.1as
cisco / ios_xe = 3.16.1s
cisco / ios_xe = 3.16.2bs
cisco / ios_xe = 3.16.2s
cisco / ios_xe = 3.16.3s
cisco / ios_xe = 3.16.4as
cisco / ios_xe = 3.16.4bs
cisco / ios_xe = 3.16.4cs
cisco / ios_xe = 3.16.4ds
cisco / ios_xe = 3.16.4es
cisco / ios_xe = 3.16.4gs
cisco / ios_xe = 3.16.5as
cisco / ios_xe = 3.16.5bs
cisco / ios_xe = 3.16.5s
cisco / ios_xe = 3.16.6bs
cisco / ios_xe = 3.16.6s
cisco / ios_xe = 3.16.7as
cisco / ios_xe = 3.16.7bs
cisco / ios_xe = 3.16.7s
cisco / ios_xe = 3.16.8s
cisco / ios_xe = 3.16.9s
cisco / ios_xe = 3.16.10s
cisco / ios_xe = 3.17.0s
cisco / ios_xe = 3.17.1as
cisco / ios_xe = 3.17.1s
cisco / ios_xe = 3.17.2s
cisco / ios_xe = 3.17.3s
cisco / ios_xe = 3.17.4s
cisco / ios_xe = 3.18.0as
cisco / ios_xe = 3.18.1asp
cisco / ios_xe = 3.18.1sp
cisco / ios_xe = 3.18.2asp
cisco / ios_xe = 3.18.3asp
cisco / ios_xe = 3.18.3bsp
cisco / ios_xe = 3.18.3sp
cisco / ios_xe = 3.18.4sp
cisco / ios_xe = 3.18.5sp
cisco / ios_xe = 3.18.6sp
cisco / ios_xe = 16.2.1
cisco / ios_xe = 16.2.2
cisco / ios_xe = 16.3.1
cisco / ios_xe = 16.3.1a
cisco / ios_xe = 16.3.2
cisco / ios_xe = 16.3.3
cisco / ios_xe = 16.3.4
cisco / ios_xe = 16.3.5
cisco / ios_xe = 16.3.6
cisco / ios_xe = 16.3.7
cisco / ios_xe = 16.3.8
cisco / ios_xe = 16.3.9
cisco / ios_xe = 16.4.1
cisco / ios_xe = 16.4.2
cisco / ios_xe = 16.4.3
cisco / ios_xe = 16.5.1
cisco / ios_xe = 16.5.1b
cisco / ios_xe = 16.5.2
cisco / ios_xe = 16.5.3
cisco / ios_xe = 16.6.1
cisco / ios_xe = 16.6.2
cisco / ios_xe = 16.6.3
cisco / ios_xe = 16.6.4
cisco / ios_xe = 16.6.4s
cisco / ios_xe = 16.6.5
cisco / ios_xe = 16.6.5b
cisco / ios_xe = 16.6.6
cisco / ios_xe = 16.7.1
cisco / ios_xe = 16.7.1a
cisco / ios_xe = 16.7.1b
cisco / ios_xe = 16.7.2
cisco / ios_xe = 16.7.3
cisco / ios_xe = 16.7.4
cisco / ios_xe = 16.8.1
cisco / ios_xe = 16.8.1a
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 = 16.9.1s
cisco / ios_xe = 16.9.2
cisco / ios_xe = 16.9.2s
cisco / ios_xe = 16.9.3
cisco / ios_xe = 16.9.3s
cisco / ios_xe = 16.9.4
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 = 16.11.1
cisco / ios_xe = 16.11.1a
cisco / ios_xe = 16.11.1b
cisco / ios_xe = 16.11.1c
cisco / ios_xe = 16.11.1s
cisco / ios_xe = 16.12.1y

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.