CVE-2016-2402

Improper Certificate Validation in OkHttp

5.9 MediumPublic exploitFix available

OkHttp before 2.7.4 and 3.x before 3.1.2 allows man-in-the-middle attackers to bypass certificate pinning by sending a certificate chain with a certificate from a non-pinned trusted CA and the pinned certificate.

Attack profile

How easy it is to exploit

Attack vector: Network
Complexity: High
Privileges needed: None
User interaction: None

What an attacker can affect

Confidentiality: None
Integrity: High
Availability: None

Exploit likelihood

1.94%Down 5.2 points since Feb 4, 2022

What each source reports

NVD Score used 5.9

Record: CVE-2016-2402
CVSS 3.1: 5.9 MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N
CVSS 2.0: 4.3 MediumAV:N/AC:M/Au:N/C:N/I:P/A:N
Weakness: CWE-295
Updated: 2026-11-02

CVE List No score

Record: CVE-2016-2402
Updated: 2026-11-02

EUVDEUVD-2022-2383 No score

Record: EUVD-2022-2383
Updated: 2026-11-03

GitHub AdvisoriesGHSA-4hc2-jh7r-wrc3 5.9

Improper Certificate Validation in OkHttp

Record: GHSA-4hc2-jh7r-wrc3
CVSS 3.1: 5.9 MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N
Weakness: CWE-295
Updated: 2026-11-02

OSV 5.9

Record: CVE-2016-2402
CVSS 3.1: 5.9 MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N
Updated: 2026-11-02

OSVGHSA-4hc2-jh7r-wrc3 5.9

Improper Certificate Validation in OkHttp

Record: GHSA-4hc2-jh7r-wrc3
CVSS 3.1: 5.9 MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N
Weakness: CWE-295
Updated: 2026-11-02

Affected products

Affected packages

Affected packages
Package	Affected	Fixed
`com.squareup.okhttp3:okhttp` Maven	through 2.7.3	2.7.4
`com.squareup.okhttp3:okhttp` Maven	3.0.0 to 3.1.1	3.1.2
`com.squareup.okhttp3:okhttp` Maven	before 2.7.4	2.7.4
`com.squareup.okhttp3:okhttp` Maven	3.0.0 up to 3.1.2, plus listed versions 3.0.13.1.03.1.1	3.1.2

Public exploits

Links only. Every CVE stores no exploit code.

Public exploits
Source	Link	Date
PoC in GitHub	ikoz/cert-pinning-flaw-poc	2016-03-20
PoC in GitHub	ikoz/certPinningVulnerableOkHttp	2016-03-30

History

History
Recorded	Changed	Sources
Nov 3, 2026	aliases	EUVD
Nov 2, 2026	first indexed	CVE List, GitHub Advisories, NVD, OSV, PoC in GitHub

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2016-2402 is a medium vulnerability (CVSS 5.9) in Squareup Okhttp, published January 30, 2017. Public exploit code exists. EPSS puts the chance of exploitation in the next 30 days at 1.94%, the 80th percentile. Fixed in com.squareup.okhttp3:okhttp 2.7.4.