Vulnerability Database

383,371

Total vulnerabilities in the database

CVE-2021-1391 — cisco / ios

Active Debug Code

A vulnerability in the dragonite debugger of Cisco IOS XE Software could allow an authenticated, local attacker to escalate from privilege level 15 to root privilege. The vulnerability is due to the presence of development testing and verification scripts that remained on the device. An attacker could exploit this vulnerability by bypassing the consent token mechanism with the residual scripts on the affected device. A successful exploit could allow the attacker to escalate from privilege level 15 to root privilege.

  • Published: Mar 24, 2021
  • Updated: Sep 13, 2026
  • CVE: CVE-2021-1391
  • Severity: Medium
  • Exploit:
  • CISA KEV:

CVSS v3:

  • Severity: Medium
  • Score: 5.1
  • AV:L/AC:L/PR:H/UI:N/S:U/C:L/I:H/A:N

CVSS v2:

  • Severity: High
  • Score: 7.2
  • AV:L/AC:L/Au:N/C:C/I:C/A:C

CWEs:

Software Affected versions
cisco / ios = 12.2(6)i1
cisco / ios = 15.0(2)se13a
cisco / ios = 15.1(3)svr1
cisco / ios = 15.1(3)svr2
cisco / ios = 15.1(3)svr3
cisco / ios = 15.1(3)svs
cisco / ios = 15.1(3)svs1
cisco / ios = 15.2(4)ea10
cisco / ios = 15.2(5)e
cisco / ios = 15.2(5)e1
cisco / ios = 15.2(5)e2
cisco / ios = 15.2(5)e2b
cisco / ios = 15.2(5)e2c
cisco / ios = 15.2(5)ea
cisco / ios = 15.2(5)ex
cisco / ios = 15.2(5a)e
cisco / ios = 15.2(5a)e1
cisco / ios = 15.2(5b)e
cisco / ios = 15.2(5c)e
cisco / ios = 15.2(6)e
cisco / ios = 15.2(6)e0a
cisco / ios = 15.2(6)e0c
cisco / ios = 15.2(6)e1
cisco / ios = 15.2(6)e1a
cisco / ios = 15.2(6)e1s
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)e2b
cisco / ios = 15.2(7)e3
cisco / ios = 15.2(7)e3k
cisco / ios = 15.2(7a)e0b
cisco / ios = 15.2(7b)e0b
cisco / ios = 15.3(3)jf13
cisco / ios_xe = 3.9.0e
cisco / ios_xe = 3.9.1e
cisco / ios_xe = 3.9.2be
cisco / ios_xe = 3.9.2e
cisco / ios_xe = 3.10.0ce
cisco / ios_xe = 3.10.0e
cisco / ios_xe = 3.10.1ae
cisco / ios_xe = 3.10.1e
cisco / ios_xe = 3.10.1se
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 = 3.11.2ae
cisco / ios_xe = 3.11.2e
cisco / ios_xe = 3.11.3ae
cisco / ios_xe = 3.11.3e
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 = 16.9.1c
cisco / ios_xe = 16.9.1d
cisco / ios_xe = 16.9.1s
cisco / ios_xe = 16.9.2
cisco / ios_xe = 16.9.2a
cisco / ios_xe = 16.9.2s
cisco / ios_xe = 16.9.3
cisco / ios_xe = 16.9.3a
cisco / ios_xe = 16.9.3h
cisco / ios_xe = 16.9.3s
cisco / ios_xe = 16.9.4
cisco / ios_xe = 16.9.4c
cisco / ios_xe = 16.9.5
cisco / ios_xe = 16.9.5f
cisco / ios_xe = 16.9.6
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 = 16.11.1c
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 = 16.12.1z
cisco / ios_xe = 16.12.1za
cisco / ios_xe = 16.12.2
cisco / ios_xe = 16.12.2a
cisco / ios_xe = 16.12.2s
cisco / ios_xe = 16.12.2t
cisco / ios_xe = 16.12.3
cisco / ios_xe = 16.12.3a
cisco / ios_xe = 16.12.3s
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 = 17.1.2
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

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.