CVE-2016-3739

Publication date 20 May 2016

Last updated 25 August 2025

Ubuntu priority

Cvss 3 Severity Score

Description

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.

Read the notes from the security team

Status

Show unmaintained releases

Package	Ubuntu Release	Status
curl	16.04 LTS xenial	Not affected
	15.10 wily	Not affected
	14.04 LTS trusty	Not affected
	12.04 LTS precise	Not affected

Notes

sbeattie

curl in ubuntu is built with gnutls

Patch details

For informational purposes only. We recommend not to cherry-pick updates. How can I get the fixes?

Package	Patch details
curl	Upstream: https://curl.haxx.se/CVE-2016-3739.patch

Severity score breakdown

CVSS version: CVSS v3.0

Base score 5.3 · Medium

Base metrics

Parameter	Value
Attack vector	Network
Attack complexity	High
Privileges required	None
User interaction	Required
Scope	Unchanged
Confidentiality impact	None
Integrity impact	High
Availability impact	None

Scores

Parameter	Value
Base score	5.3 · Medium
Exploitability score	-
Impact score	-

Vector: CVSS:3.0/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:H/A:N