Vulnerability Database

328,409

Total vulnerabilities in the database

CVE-2017-3737

OpenSSL 1.0.2 (starting from version 1.0.2b) introduced an "error state" mechanism. The intent was that if a fatal error occurred during a handshake then OpenSSL would move into the error state and would immediately fail if you attempted to continue the handshake. This works as designed for the explicit handshake functions (SSL_do_handshake(), SSL_accept() and SSL_connect()), however due to a bug it does not work correctly if SSL_read() or SSL_write() is called directly. In that scenario, if the handshake fails then a fatal error will be returned in the initial function call. If SSL_read()/SSL_write() is subsequently called by the application for the same SSL object then it will succeed and the data is passed without being decrypted/encrypted directly from the SSL/TLS record layer. In order to exploit this issue an application bug would have to be present that resulted in a call to SSL_read()/SSL_write() being issued after having already received a fatal error. OpenSSL version 1.0.2b-1.0.2m are affected. Fixed in OpenSSL 1.0.2n. OpenSSL 1.1.0 is not affected.

  • Published: Dec 7, 2017
  • Updated: Nov 9, 2025
  • CVE: CVE-2017-3737
  • Severity: Low
  • Exploit:

CVSS v2:

  • Severity: Low
  • Score: 4.3
  • AV:N/AC:M/Au:N/C:P/I:N/A:N
Software From Fixed in
openssl / openssl 1.0.2e 1.0.2e.x
openssl / openssl 1.0.2j 1.0.2j.x
openssl / openssl 1.0.2b 1.0.2b.x
openssl / openssl 1.0.2g 1.0.2g.x
openssl / openssl 1.0.2h 1.0.2h.x
openssl / openssl 1.0.2c 1.0.2c.x
openssl / openssl 1.0.2f 1.0.2f.x
openssl / openssl 1.0.2i 1.0.2i.x
openssl / openssl 1.0.2d 1.0.2d.x
openssl / openssl 1.0.2k 1.0.2k.x
openssl / openssl 1.0.2l 1.0.2l.x
openssl / openssl 1.0.2m 1.0.2m.x
debian / debian_linux 9.0 9.0.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.