Vulnerability Database

393,392

Total vulnerabilities in the database

CVE-2017-3849 — cisco / ios

Improper Input Validation

A vulnerability in the Autonomic Networking Infrastructure (ANI) registrar feature of Cisco IOS Software (possibly 15.2 through 15.6) and Cisco IOS XE Software (possibly 3.7 through 3.18, and 16) could allow an unauthenticated, adjacent attacker to cause a denial of service (DoS) condition. The vulnerability is due to incomplete input validation on certain crafted packets. An attacker could exploit this vulnerability by sending a crafted autonomic network channel discovery packet to a device that has all the following characteristics: (1) running a Cisco IOS Software or Cisco IOS XE Software release that supports the ANI feature; (2) configured as an autonomic registrar; (3) has a whitelist configured. An exploit could allow the attacker to cause the affected device to reload. Note: Autonomic networking should be configured with a whitelist. Do not remove the whitelist as a workaround. Cisco Bug IDs: CSCvc42717.

  • Published: Mar 21, 2017
  • Updated: Oct 3, 2026
  • CVE: CVE-2017-3849
  • Severity: Medium
  • Exploit:
  • CISA KEV:

CVSS v2:

  • Severity: Medium
  • Score: 6.1
  • AV:A/AC:L/Au:N/C:N/I:N/A:C

CWEs:

Software Affected versions
cisco / ios = 15.2(3)e
cisco / ios = 15.2(3)e1
cisco / ios = 15.2(3)e2
cisco / ios = 15.2(3)e3
cisco / ios = 15.2(4)e
cisco / ios = 15.2(4)e1
cisco / ios = 15.2(4)e2
cisco / ios = 15.2(4)e3
cisco / ios = 15.2(5)e
cisco / ios = 15.2(5)e1
cisco / ios = 15.2(5a)e
cisco / ios = 15.2(5b)e
cisco / ios = 15.3(3)s
cisco / ios = 15.3(3)s1
cisco / ios = 15.3(3)s2
cisco / ios = 15.3(3)s3
cisco / ios = 15.3(3)s4
cisco / ios = 15.3(3)s5
cisco / ios = 15.3(3)s6
cisco / ios = 15.3(3)s8
cisco / ios = 15.3(3)s9
cisco / ios = 15.4(1)s
cisco / ios = 15.4(1)s1
cisco / ios = 15.4(1)s2
cisco / ios = 15.4(1)s3
cisco / ios = 15.4(1)s4
cisco / ios = 15.4(2)s1
cisco / ios = 15.4(2)s2
cisco / ios = 15.4(2)s3
cisco / ios = 15.4(2)s4
cisco / ios = 15.4(3)s
cisco / ios = 15.4(3)s1
cisco / ios = 15.4(3)s2
cisco / ios = 15.4(3)s3
cisco / ios = 15.4(3)s4
cisco / ios = 15.4(3)s5
cisco / ios = 15.4(3)s6
cisco / ios = 15.4(3)s6a
cisco / ios = 15.5(1)s
cisco / ios = 15.5(1)s1
cisco / ios = 15.5(1)s2
cisco / ios = 15.5(1)s3
cisco / ios = 15.5(1)s4
cisco / ios = 15.5(2)s
cisco / ios = 15.5(2)s1
cisco / ios = 15.5(2)s2
cisco / ios = 15.5(2)s3
cisco / ios = 15.5(2)s4
cisco / ios = 15.5(3)s
cisco / ios = 15.5(3)s0a
cisco / ios = 15.5(3)s1
cisco / ios = 15.5(3)s1a
cisco / ios = 15.5(3)s2
cisco / ios = 15.5(3)s3
cisco / ios = 15.5(3)s4
cisco / ios = 15.5(3)s5
cisco / ios = 15.5(3)sn
cisco / ios = 15.6(1)s
cisco / ios = 15.6(1)s1
cisco / ios = 15.6(1)s2
cisco / ios = 15.6(1)s3
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(2)s
cisco / ios = 15.6(2)s1
cisco / ios = 15.6(2)s2
cisco / ios = 15.6(2)sn
cisco / ios = 15.6(2)sp
cisco / ios = 15.6(2)sp1
cisco / ios = 15.6(2)t
cisco / ios = 15.6(2)t1
cisco / ios = 15.6(2)t2
cisco / ios = 15.6(3)m
cisco / ios = 15.6(3)m0a
cisco / ios = 15.6(3)m1
cisco / ios_xe = 3.7.0e
cisco / ios_xe = 3.7.1e
cisco / ios_xe = 3.7.2e
cisco / ios_xe = 3.7.3e
cisco / ios_xe = 3.7.4e
cisco / ios_xe = 3.7.5e
cisco / ios_xe = 3.8.0e
cisco / ios_xe = 3.8.1e
cisco / ios_xe = 3.8.2e
cisco / ios_xe = 3.8.3e
cisco / ios_xe = 3.9.0e
cisco / ios_xe = 3.9.1e
cisco / ios_xe = 3.10.0s
cisco / ios_xe = 3.10.1s
cisco / ios_xe = 3.10.1xbs
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 = 3.11.0s
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 = 3.12.1s
cisco / ios_xe = 3.12.2s
cisco / ios_xe = 3.12.3s
cisco / ios_xe = 3.12.4s
cisco / ios_xe = 3.13.0as
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 = 3.13.6s
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 = 3.16.3as
cisco / ios_xe = 3.16.3s
cisco / ios_xe = 3.16.4as
cisco / ios_xe = 3.16.4bs
cisco / ios_xe = 3.16.4ds
cisco / ios_xe = 3.16.4s
cisco / ios_xe = 3.16.5s
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 = 3.18.0as
cisco / ios_xe = 3.18.0s
cisco / ios_xe = 3.18.0sp
cisco / ios_xe = 3.18.1asp
cisco / ios_xe = 3.18.1bsp
cisco / ios_xe = 3.18.1csp
cisco / ios_xe = 3.18.1s
cisco / ios_xe = 3.18.1sp
cisco / ios_xe = 3.18.2s
cisco / ios_xe = 3.18.3vs

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.