Vulnerability Database

346,508

Total vulnerabilities in the database

CVE-2021-1433 — cisco / ios_xe

Improper Restriction of Operations within the Bounds of a Memory Buffer

A vulnerability in the vDaemon process in Cisco IOS XE SD-WAN Software could allow an unauthenticated, remote attacker to cause a buffer overflow on an affected device. This vulnerability is due to insufficient bounds checking when the device processes traffic. An attacker could exploit this vulnerability by sending crafted traffic to the device. The attacker must have a man-in-the-middle position between Cisco vManage and an associated device that is running an affected version of Cisco IOS XE SD-WAN Software. An exploit could allow the attacker to conduct a controllable buffer overflow attack (and possibly execute arbitrary commands as the root user) or cause a device reload, resulting in a denial of service (DoS) condition.

  • Published: Mar 24, 2021
  • Updated: Nov 16, 2025
  • CVE: CVE-2021-1433
  • Severity: High
  • Exploit:

CVSS v3:

  • Severity: High
  • Score: 8.1
  • AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS v2:

  • Severity: High
  • Score: 9.3
  • AV:N/AC:M/Au:N/C:C/I:C/A:C

CWEs:

Software From Fixed in
cisco / ios_xe 16.12.1 16.12.1.x
cisco / ios_xe 16.12.1c 16.12.1c.x
cisco / ios_xe 16.12.1t 16.12.1t.x
cisco / ios_xe 16.12.1s 16.12.1s.x
cisco / ios_xe 16.12.1a 16.12.1a.x
cisco / ios_xe 16.12.1x 16.12.1x.x
cisco / ios_xe 16.12.1w 16.12.1w.x
cisco / ios_xe 16.12.1y 16.12.1y.x
cisco / ios_xe 16.12.2 16.12.2.x
cisco / ios_xe 16.12.2a 16.12.2a.x
cisco / ios_xe 16.12.3 16.12.3.x
cisco / ios_xe 17.2.1 17.2.1.x
cisco / ios_xe 16.12.2t 16.12.2t.x
cisco / ios_xe 16.12.2s 16.12.2s.x
cisco / ios_xe 16.12.3a 16.12.3a.x
cisco / ios_xe 17.2.1a 17.2.1a.x
cisco / ios_xe 3.15.2xbs 3.15.2xbs.x
cisco / ios_xe 17.2.1v 17.2.1v.x
cisco / ios_xe 16.12.1z 16.12.1z.x
cisco / ios_xe 16.12.3s 16.12.3s.x
cisco / ios_xe 3.15.1xbs 3.15.1xbs.x
cisco / ios_xe 17.2.1r 17.2.1r.x
cisco / ios_xe 16.12.1za 16.12.1za.x

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.