CVE-2016-3739

MEDIUMNVD 5.35.3—
EchelonGraph scoreMEDIUM confidence

Score 5.3 from GitHub Security Advisory published 2022-05-14. NVD baseline CVSS 5.3; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
5.3
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS: 6%CVSS: 5.3Exploit: NoneExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

The (1) mbed_connect_step1 function in lib/vtls/mbedtls.c and (2) polarssl_connect_step1 function in lib/vtls/polarssl.c in cURL and libcurl before 7.49.0, when using SSLv3 or making a TLS connection to a URL that uses a numerical IP address, allow remote attackers to spoof servers via an arbitrary valid certificate.

CVSS v3
5.3
EG Score
5.3(medium)
EG Risk
31(Track)
EG Risk 31/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity53% × 45%
Exploitation6% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS
92.9%
KEV
Not listed

Published

May 20, 2016

Last Modified

May 6, 2026

References (22)

Data Freshness Timeline

(refreshed 12× in last 7d / 41× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-07-23 14:14 UTCEPSS rescore
  2. 2026-07-23 01:22 UTCEG score recompute
  3. 2026-07-22 22:02 UTCEG score recompute
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  65. 2026-05-22 20:15 UTCGHSA enrichment
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Frequently asked(5)

What is CVE-2016-3739?
CVE-2016-3739 is a medium vulnerability published on May 20, 2016. The (1) mbedconnectstep1 function in lib/vtls/mbedtls.c and (2) polarsslconnectstep1 function in lib/vtls/polarssl.c in cURL and libcurl before 7.49.0, when using SSLv3 or making a TLS connection to a URL that uses a numerical IP address, allow remote attackers to spoof servers via an arbitrary…
When was CVE-2016-3739 disclosed?
CVE-2016-3739 was first published in the National Vulnerability Database on May 20, 2016, with the most recent update on May 6, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2016-3739 actively exploited?
CVE-2016-3739 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 92.9% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2016-3739?
CVE-2016-3739 has a CVSS v3 base score of 5.3 (NVD).
How do I remediate CVE-2016-3739?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2016-3739, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

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