Vulnerability Database

393,544

Total vulnerabilities in the database

CVE-2019-1757 — cisco / ios

Improper Certificate Validation

A vulnerability in the Cisco Smart Call Home feature of Cisco IOS and IOS XE Software could allow an unauthenticated, remote attacker to gain unauthorized read access to sensitive data using an invalid certificate. The vulnerability is due to insufficient certificate validation by the affected software. An attacker could exploit this vulnerability by supplying a crafted certificate to an affected device. A successful exploit could allow the attacker to conduct man-in-the-middle attacks to decrypt confidential information on user connections to the affected software.

  • Published: Mar 28, 2019
  • Updated: Oct 4, 2026
  • CVE: CVE-2019-1757
  • Severity: Medium
  • Exploit:
  • CISA KEV:

CVSS v3:

  • Severity: Medium
  • Score: 5.9
  • AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N

CVSS v2:

  • Severity: Medium
  • Score: 4.3
  • AV:N/AC:M/Au:N/C:P/I:N/A:N
Software Affected versions
cisco / ios = 2.3
cisco / ios = 12.2(6)i1
cisco / ios = 12.4(25e)jap1m
cisco / ios = 12.4(25e)jap2
cisco / ios = 12.4(25e)jap26
cisco / ios = 12.4(25e)jaz1
cisco / ios = 15.1(2)sg8a
cisco / ios = 15.1(3)svg3d
cisco / ios = 15.1(3)svi1b
cisco / ios = 15.1(3)svm3
cisco / ios = 15.1(3)svn2
cisco / ios = 15.1(3)svo1
cisco / ios = 15.1(3)svo2
cisco / ios = 15.1(3)svp1
cisco / ios = 15.1(4)m12c
cisco / ios = 15.2(2)e4
cisco / ios = 15.2(2)e5
cisco / ios = 15.2(2)e5a
cisco / ios = 15.2(2)e5b
cisco / ios = 15.2(2)e6
cisco / ios = 15.2(2)e7
cisco / ios = 15.2(2)e7b
cisco / ios = 15.2(2)e8
cisco / ios = 15.2(3)e4
cisco / ios = 15.2(3)e5
cisco / ios = 15.2(3)ea1
cisco / ios = 15.2(4)e2
cisco / ios = 15.2(4)e3
cisco / ios = 15.2(4)e4
cisco / ios = 15.2(4)e5
cisco / ios = 15.2(4)e5a
cisco / ios = 15.2(4)e6
cisco / ios = 15.2(4)ea8
cisco / ios = 15.2(4)ea9
cisco / ios = 15.2(4)jaz1
cisco / ios = 15.2(4)jn1
cisco / ios = 15.2(4a)ea5
cisco / ios = 15.2(4m)e2
cisco / ios = 15.2(4m)e3
cisco / ios = 15.2(4n)e2
cisco / ios = 15.2(4o)e2
cisco / ios = 15.2(4o)e3
cisco / ios = 15.2(4p)e1
cisco / ios = 15.2(4q)e1
cisco / ios = 15.2(4s)e1
cisco / ios = 15.2(4s)e2
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 = 15.3(3)ja1n
cisco / ios = 15.3(3)jd15
cisco / ios = 15.3(3)jda15
cisco / ios = 15.3(3)jf35
cisco / ios = 15.3(3)ji
cisco / ios = 15.3(3)ji2
cisco / ios = 15.3(3)jn1
cisco / ios = 15.3(3)jn2
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)s6
cisco / ios = 15.5(3)s6a
cisco / ios = 15.5(3)s6b
cisco / ios = 15.5(3)s7
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)s4
cisco / ios = 15.6(1)sn
cisco / ios = 15.6(1)sn1
cisco / ios = 15.6(1)sn2
cisco / ios = 15.6(1)sn3
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)s
cisco / ios = 15.6(2)s1
cisco / ios = 15.6(2)s2
cisco / ios = 15.6(2)s3
cisco / ios = 15.6(2)s4
cisco / ios = 15.6(2)sn
cisco / ios = 15.6(2)sp
cisco / ios = 15.6(2)sp1
cisco / ios = 15.6(2)sp2
cisco / ios = 15.6(2)sp3
cisco / ios = 15.6(2)sp3b
cisco / ios = 15.6(2)sp4
cisco / ios = 15.6(2)t
cisco / ios = 15.6(2)t0a
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)sn
cisco / ios = 15.6(4)sn
cisco / ios = 15.6(5)sn
cisco / ios = 15.6(6)sn
cisco / ios = 15.6(7)sn
cisco / ios = 15.7(3)m
cisco / ios = 15.7(3)m0a
cisco / ios = 15.7(3)m1
cisco / ios = 15.7(3)m2
cisco / ios_xe = 3.6.4e
cisco / ios_xe = 3.6.5ae
cisco / ios_xe = 3.6.5be
cisco / ios_xe = 3.6.5e
cisco / ios_xe = 3.6.6e
cisco / ios_xe = 3.6.7ae
cisco / ios_xe = 3.6.7be
cisco / ios_xe = 3.6.7e
cisco / ios_xe = 3.6.8e
cisco / ios_xe = 3.7.4e
cisco / ios_xe = 3.7.5e
cisco / ios_xe = 3.8.2e
cisco / ios_xe = 3.8.3e
cisco / ios_xe = 3.8.4e
cisco / ios_xe = 3.8.5ae
cisco / ios_xe = 3.8.5e
cisco / ios_xe = 3.8.6e
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 = 3.16.1as
cisco / ios_xe = 3.16.1s
cisco / ios_xe = 3.16.2as
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 = 3.16.4cs
cisco / ios_xe = 3.16.4ds
cisco / ios_xe = 3.16.4es
cisco / ios_xe = 3.16.4gs
cisco / ios_xe = 3.16.4s
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 = 3.17.0s
cisco / ios_xe = 3.17.1as
cisco / ios_xe = 3.17.1s
cisco / ios_xe = 3.17.3s
cisco / ios_xe = 3.17.4s
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 = 3.18.1gsp
cisco / ios_xe = 3.18.1hsp
cisco / ios_xe = 3.18.1isp
cisco / ios_xe = 3.18.1s
cisco / ios_xe = 3.18.1sp
cisco / ios_xe = 3.18.2asp
cisco / ios_xe = 3.18.2s
cisco / ios_xe = 3.18.2sp
cisco / ios_xe = 3.18.3asp
cisco / ios_xe = 3.18.3bsp
cisco / ios_xe = 3.18.3s
cisco / ios_xe = 3.18.3sp
cisco / ios_xe = 3.18.4s
cisco / ios_xe = 3.18.4sp
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 = 16.3.5b
cisco / ios_xe = 16.3.6
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 = 16.5.1a
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 = 16.7.1
cisco / ios_xe = 16.7.1a
cisco / ios_xe = 16.7.1b
cisco / ios_xe = 16.7.2
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 = 16.8.1s
cisco / ios_xe = 16.8.2
cisco / ios_xe = 16.9.1b
cisco / ios_xe = 16.9.1c
cisco / ios_xe = 16.9.1s

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.