Vulnerability Database

346,508

Total vulnerabilities in the database

CVE-2023-20187 — cisco / ios_xe

Use of Out-of-range Pointer Offset

A vulnerability in the Multicast Leaf Recycle Elimination (mLRE) feature of Cisco IOS XE Software for Cisco ASR 1000 Series Aggregation Services Routers could allow an unauthenticated, remote attacker to cause the affected device to reload, resulting in a denial of service (DoS) condition.

This vulnerability is due to incorrect handling of certain IPv6 multicast packets when they are fanned out more than seven times on an affected device. An attacker could exploit this vulnerability by sending a specific IPv6 multicast or IPv6 multicast VPN (MVPNv6) packet through the affected device. A successful exploit could allow the attacker to cause a reload of the affected device, resulting in a DoS condition.

  • Published: Sep 27, 2023
  • Updated: Nov 16, 2025
  • CVE: CVE-2023-20187
  • Severity: High
  • Exploit:

CVSS v3:

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

CWEs:

Software From Fixed in
cisco / ios_xe 3.7.1s 3.7.1s.x
cisco / ios_xe 3.7.2s 3.7.2s.x
cisco / ios_xe 3.7.2ts 3.7.2ts.x
cisco / ios_xe 3.7.3s 3.7.3s.x
cisco / ios_xe 3.7.4s 3.7.4s.x
cisco / ios_xe 3.7.5s 3.7.5s.x
cisco / ios_xe 3.7.6s 3.7.6s.x
cisco / ios_xe 3.7.7s 3.7.7s.x
cisco / ios_xe 3.8.0s 3.8.0s.x
cisco / ios_xe 3.8.1s 3.8.1s.x
cisco / ios_xe 3.8.2s 3.8.2s.x
cisco / ios_xe 3.9.0s 3.9.0s.x
cisco / ios_xe 3.9.1s 3.9.1s.x
cisco / ios_xe 3.9.2s 3.9.2s.x
cisco / ios_xe 3.10.0s 3.10.0s.x
cisco / ios_xe 3.10.1s 3.10.1s.x
cisco / ios_xe 3.10.1xbs 3.10.1xbs.x
cisco / ios_xe 3.10.2s 3.10.2s.x
cisco / ios_xe 3.10.3s 3.10.3s.x
cisco / ios_xe 3.10.4s 3.10.4s.x
cisco / ios_xe 3.10.5s 3.10.5s.x
cisco / ios_xe 3.10.6s 3.10.6s.x
cisco / ios_xe 3.10.7s 3.10.7s.x
cisco / ios_xe 3.10.8as 3.10.8as.x
cisco / ios_xe 3.10.8s 3.10.8s.x
cisco / ios_xe 3.10.9s 3.10.9s.x
cisco / ios_xe 3.10.10s 3.10.10s.x
cisco / ios_xe 3.11.0s 3.11.0s.x
cisco / ios_xe 3.11.1s 3.11.1s.x
cisco / ios_xe 3.11.2s 3.11.2s.x
cisco / ios_xe 3.11.3s 3.11.3s.x
cisco / ios_xe 3.11.4s 3.11.4s.x
cisco / ios_xe 3.12.0s 3.12.0s.x
cisco / ios_xe 3.12.1s 3.12.1s.x
cisco / ios_xe 3.12.2s 3.12.2s.x
cisco / ios_xe 3.12.3s 3.12.3s.x
cisco / ios_xe 3.12.4s 3.12.4s.x
cisco / ios_xe 3.13.0s 3.13.0s.x
cisco / ios_xe 3.13.1s 3.13.1s.x
cisco / ios_xe 3.13.2as 3.13.2as.x
cisco / ios_xe 3.13.2s 3.13.2s.x
cisco / ios_xe 3.13.3s 3.13.3s.x
cisco / ios_xe 3.13.4s 3.13.4s.x
cisco / ios_xe 3.13.5as 3.13.5as.x
cisco / ios_xe 3.13.5s 3.13.5s.x
cisco / ios_xe 3.13.6as 3.13.6as.x
cisco / ios_xe 3.13.6s 3.13.6s.x
cisco / ios_xe 3.13.7s 3.13.7s.x
cisco / ios_xe 3.13.8s 3.13.8s.x
cisco / ios_xe 3.13.9s 3.13.9s.x
cisco / ios_xe 3.13.10s 3.13.10s.x
cisco / ios_xe 3.14.0s 3.14.0s.x
cisco / ios_xe 3.14.1s 3.14.1s.x
cisco / ios_xe 3.14.2s 3.14.2s.x
cisco / ios_xe 3.14.3s 3.14.3s.x
cisco / ios_xe 3.14.4s 3.14.4s.x
cisco / ios_xe 3.15.0s 3.15.0s.x
cisco / ios_xe 3.15.1s 3.15.1s.x
cisco / ios_xe 3.15.2s 3.15.2s.x
cisco / ios_xe 3.15.3s 3.15.3s.x
cisco / ios_xe 3.15.4s 3.15.4s.x
cisco / ios_xe 3.16.0s 3.16.0s.x
cisco / ios_xe 3.16.1as 3.16.1as.x
cisco / ios_xe 3.16.2bs 3.16.2bs.x
cisco / ios_xe 3.16.2s 3.16.2s.x
cisco / ios_xe 3.16.3s 3.16.3s.x
cisco / ios_xe 3.16.4as 3.16.4as.x
cisco / ios_xe 3.16.4bs 3.16.4bs.x
cisco / ios_xe 3.16.5s 3.16.5s.x
cisco / ios_xe 3.16.6bs 3.16.6bs.x
cisco / ios_xe 3.16.6s 3.16.6s.x
cisco / ios_xe 3.16.7as 3.16.7as.x
cisco / ios_xe 3.16.7bs 3.16.7bs.x
cisco / ios_xe 3.16.7s 3.16.7s.x
cisco / ios_xe 3.16.8s 3.16.8s.x
cisco / ios_xe 3.16.9s 3.16.9s.x
cisco / ios_xe 3.16.10s 3.16.10s.x
cisco / ios_xe 3.17.0s 3.17.0s.x
cisco / ios_xe 3.17.1as 3.17.1as.x
cisco / ios_xe 3.17.1s 3.17.1s.x
cisco / ios_xe 3.17.2s 3.17.2s.x
cisco / ios_xe 3.17.3s 3.17.3s.x
cisco / ios_xe 3.17.4s 3.17.4s.x
cisco / ios_xe 16.2.1 16.2.1.x
cisco / ios_xe 16.2.2 16.2.2.x
cisco / ios_xe 16.3.1 16.3.1.x
cisco / ios_xe 16.3.1a 16.3.1a.x
cisco / ios_xe 16.3.2 16.3.2.x
cisco / ios_xe 16.3.3 16.3.3.x
cisco / ios_xe 16.3.4 16.3.4.x
cisco / ios_xe 16.3.5 16.3.5.x
cisco / ios_xe 16.3.6 16.3.6.x
cisco / ios_xe 16.3.7 16.3.7.x
cisco / ios_xe 16.3.8 16.3.8.x
cisco / ios_xe 16.3.9 16.3.9.x
cisco / ios_xe 16.3.10 16.3.10.x
cisco / ios_xe 16.3.11 16.3.11.x
cisco / ios_xe 16.4.1 16.4.1.x
cisco / ios_xe 16.4.2 16.4.2.x
cisco / ios_xe 16.4.3 16.4.3.x
cisco / ios_xe 16.5.1 16.5.1.x
cisco / ios_xe 16.5.1b 16.5.1b.x
cisco / ios_xe 16.5.2 16.5.2.x
cisco / ios_xe 16.5.3 16.5.3.x
cisco / ios_xe 16.6.1 16.6.1.x
cisco / ios_xe 16.6.2 16.6.2.x
cisco / ios_xe 16.6.3 16.6.3.x
cisco / ios_xe 16.6.4 16.6.4.x
cisco / ios_xe 16.6.5 16.6.5.x
cisco / ios_xe 16.6.6 16.6.6.x
cisco / ios_xe 16.6.7 16.6.7.x
cisco / ios_xe 16.6.8 16.6.8.x
cisco / ios_xe 16.6.9 16.6.9.x
cisco / ios_xe 16.6.10 16.6.10.x
cisco / ios_xe 16.7.1 16.7.1.x
cisco / ios_xe 16.7.2 16.7.2.x
cisco / ios_xe 16.7.3 16.7.3.x
cisco / ios_xe 16.8.1 16.8.1.x
cisco / ios_xe 16.8.1s 16.8.1s.x
cisco / ios_xe 16.8.2 16.8.2.x
cisco / ios_xe 16.8.3 16.8.3.x
cisco / ios_xe 16.9.1 16.9.1.x
cisco / ios_xe 16.9.1s 16.9.1s.x
cisco / ios_xe 16.9.2 16.9.2.x
cisco / ios_xe 16.9.3 16.9.3.x
cisco / ios_xe 16.9.4 16.9.4.x
cisco / ios_xe 16.9.5 16.9.5.x
cisco / ios_xe 16.9.6 16.9.6.x
cisco / ios_xe 16.9.7 16.9.7.x
cisco / ios_xe 16.9.8 16.9.8.x
cisco / ios_xe 16.10.1 16.10.1.x
cisco / ios_xe 16.10.1a 16.10.1a.x
cisco / ios_xe 16.10.1e 16.10.1e.x
cisco / ios_xe 16.10.1s 16.10.1s.x
cisco / ios_xe 16.10.2 16.10.2.x
cisco / ios_xe 16.10.3 16.10.3.x
cisco / ios_xe 16.11.1 16.11.1.x
cisco / ios_xe 16.11.1a 16.11.1a.x
cisco / ios_xe 16.11.1s 16.11.1s.x
cisco / ios_xe 16.11.2 16.11.2.x
cisco / ios_xe 16.12.1 16.12.1.x
cisco / ios_xe 16.12.1a 16.12.1a.x
cisco / ios_xe 16.12.1c 16.12.1c.x
cisco / ios_xe 16.12.1s 16.12.1s.x
cisco / ios_xe 16.12.2 16.12.2.x
cisco / ios_xe 16.12.2s 16.12.2s.x
cisco / ios_xe 16.12.3 16.12.3.x
cisco / ios_xe 16.12.3s 16.12.3s.x
cisco / ios_xe 16.12.4 16.12.4.x
cisco / ios_xe 16.12.5 16.12.5.x
cisco / ios_xe 16.12.6 16.12.6.x
cisco / ios_xe 16.12.7 16.12.7.x
cisco / ios_xe 16.12.8 16.12.8.x
cisco / ios_xe 17.1.1 17.1.1.x
cisco / ios_xe 17.1.1s 17.1.1s.x
cisco / ios_xe 17.1.1t 17.1.1t.x
cisco / ios_xe 17.1.3 17.1.3.x
cisco / ios_xe 17.2.1 17.2.1.x
cisco / ios_xe 17.2.1r 17.2.1r.x
cisco / ios_xe 17.2.1v 17.2.1v.x
cisco / ios_xe 17.2.2 17.2.2.x
cisco / ios_xe 17.2.3 17.2.3.x
cisco / ios_xe 17.3.1 17.3.1.x
cisco / ios_xe 17.3.1a 17.3.1a.x
cisco / ios_xe 17.3.2 17.3.2.x
cisco / ios_xe 17.3.3 17.3.3.x
cisco / ios_xe 17.3.4 17.3.4.x
cisco / ios_xe 17.3.4a 17.3.4a.x
cisco / ios_xe 17.3.5 17.3.5.x
cisco / ios_xe 17.3.6 17.3.6.x
cisco / ios_xe 17.3.7 17.3.7.x
cisco / ios_xe 17.4.1 17.4.1.x
cisco / ios_xe 17.4.1a 17.4.1a.x
cisco / ios_xe 17.4.1b 17.4.1b.x
cisco / ios_xe 17.4.2 17.4.2.x
cisco / ios_xe 17.5.1 17.5.1.x
cisco / ios_xe 17.5.1a 17.5.1a.x
cisco / ios_xe 17.5.1b 17.5.1b.x
cisco / ios_xe 17.5.1c 17.5.1c.x
cisco / ios_xe 17.6.1 17.6.1.x
cisco / ios_xe 17.6.1a 17.6.1a.x
cisco / ios_xe 17.6.2 17.6.2.x
cisco / ios_xe 17.6.3 17.6.3.x
cisco / ios_xe 17.6.3a 17.6.3a.x
cisco / ios_xe 17.6.4 17.6.4.x
cisco / ios_xe 17.6.5 17.6.5.x
cisco / ios_xe 17.7.1 17.7.1.x
cisco / ios_xe 17.7.1a 17.7.1a.x
cisco / ios_xe 17.7.2 17.7.2.x
cisco / ios_xe 17.8.1 17.8.1.x
cisco / ios_xe 17.8.1a 17.8.1a.x
cisco / ios_xe 17.9.1 17.9.1.x
cisco / ios_xe 17.9.1a 17.9.1a.x
cisco / ios_xe 17.9.2 17.9.2.x
cisco / ios_xe 17.9.2a 17.9.2a.x
cisco / ios_xe 17.9.3 17.9.3.x
cisco / ios_xe 17.9.3a 17.9.3a.x
cisco / ios_xe 17.10.1 17.10.1.x
cisco / ios_xe 17.10.1a 17.10.1a.x
cisco / ios_xe 17.11.1 17.11.1.x
cisco / ios_xe 17.11.1a 17.11.1a.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.