How severe is CVE-2016-2402?

CVE-2016-2402 has a CVSS score of 5.9/10, rated MEDIUM. Review your exposure and patch according to your risk tolerance.

Which packages are affected by CVE-2016-2402?

CVE-2016-2402 affects the following packages: com.squareup.okhttp3:okhttp (Maven), com.squareup.okhttp3:okhttp (Maven). Ecosystems affected: Maven.

How do I fix CVE-2016-2402?

Update com.squareup.okhttp3:okhttp to 2.7.4 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2016-2402 is resolved across your whole dependency graph.

How do I detect CVE-2016-2402 in my Maven dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for com.squareup.okhttp3:okhttp, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2016-2402 if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Is CVE-2016-2402 actively exploited in the wild?

Yes. There are 4 known exploit references for CVE-2016-2402, including 2 in-the-wild exploitations observed on GitHub and other sources. Treat this as actively exploitable and prioritize patching immediately. All exploit code should only be run in an isolated sandbox environment for research or authorized testing — never against production systems without explicit written authorization.

What is the EPSS score for CVE-2016-2402?

CVE-2016-2402 has an EPSS (Exploit Prediction Scoring System) score of 1.9%, placing it in the 80th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2016-2402?

CVE-2016-2402 is classified as CWE-295 (CWE-295). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2016-2402 published, and has it been updated?

CVE-2016-2402 was published on January 30, 2017 and was last updated on October 24, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

☕

☕ Maven

Not in CISA KEV

MEDIUM severity

CVE-2016-2402 — okhttp

MEDIUM

CVE-2016-2402 is a medium-severity (CVSS 5.9) CWE-295 vulnerability in com.squareup.okhttp3:okhttp. 4 public exploit or proof-of-concept references are indexed, so weaponization risk is real. A fix is available for com.squareup.okhttp3:okhttp — see the affected versions and patch details below.

Improper Certificate Validation in OkHttp

Also known asGHSA-4hc2-jh7r-wrc3

Published

Jan 30, 2017

Updated

Oct 24, 2026

Affected

2 pkgs

Patched

2 / 2

Exploits

4 known

Exploitation data as of Nov 6, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗

1.9%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs80th percentile — riskier than 80% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

2 pkgs affected

☕com.squareup.okhttp3:okhttp☕com.squareup.okhttp3:okhttp

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Maven packages — download data is not available via public APIs for these ecosystems.

Description

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.

Affected Packages

2 total 2 fixed

Ecosystem	Package	Vulnerable range	Fix
☕Maven	`com.squareup.okhttp3:okhttp`	all versions	2.7.4`com.squareup.okhttp3:okhttp:2.7.4`
☕Maven	`com.squareup.okhttp3:okhttp`	≥ 3.0.0&&< 3.1.2	3.1.2`com.squareup.okhttp3:okhttp:3.1.2`

Affected Products

2 products · 6 configurations

Application

okhttpsquareup

≤ 2.7.3

range

Application

okhttp3squareup

4 versions

3.0.03.0.13.1.03.1.1

Exploits & PoCs

Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.

OkHttp before 2.7.4 and 3.x before 3.1.2 allows man-in-the-middle attack…

github.comGithubMar 2016

Report on github.com

github.comGithubMar 2016

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for com.squareup.okhttp3:okhttp, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update com.squareup.okhttp3:okhttp to 2.7.4 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2016-2402 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Frequently Asked Questions

O3 Security · Impact-Aware SCA

Is CVE-2016-2402 in your dependencies?

Find it across Maven, including transitive dependencies.

Scan my dependencies How O3 SCA works

CVSS Score

5.9/10CVSS v3 base

Vector breakdown

Attack Vector

Network

Attack Complexity

High

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

High

Availability

None

Raw vector

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N

CWE Classification

CWE-295CWE-295

Weaponization

No Nuclei template or Metasploit module yet. 4 public proof-of-concept references are listed on this page.

OpenSSF Scorecard

Package health score

okhttp

7.1/10

Code-Review8/10

Maintained10/10

Branch-ProtectionN/A

Assessed Nov 2, 2026

Timeline

First exploit

Mar 20, 2016

Disclosed

Jan 30, 2017

Last updated

Oct 24, 2026

Identifiers

CVE-2016-2402

GHSA-4hc2-jh7r-wrc3

References

Advisoryopenwall.com Advisoryopenwall.com Advisorykoz.io · pinning cve 2016 2402 Advisorypublicobject.com · okhttp certificate pinning vulnerability Advisorynvd.nist.gov · CVE 2016 2402 Weblists.apache.org · rd0e44e8ef71eeaaa3cf3d1b8b41eb25894372e2995ec908ce7624d26@<commits.pulsar.apache.org>Webkoz.io · pinning cve 2016 2402 Weblists.apache.org · rd0e44e8ef71eeaaa3cf3d1b8b41eb25894372e2995ec908ce7624d26@<commits.pulsar.apache.org>Webpublicobject.com · okhttp certificate pinning vulnerability Packagegithub.com · okhttp

Related vulnerabilities

Also affects okhttp

This CVE is medium severity; 1 of 1 other CVE affecting okhttp is rated as high or higher (top: high).

CVE-2021-0341

Same weakness: CWE-295

This CVE is medium severity; 6 of 7 other CVEs with CWE-295 are rated as high or higher (top: critical).

CVE-2026-118780CVE-2026-119190GHSA-5xjx-3w67-w9x9CVE-2026-109383GHSA-6q48-6c7w-9gw2GHSA-hq85-5cpj-mr62CVE-2026-70194Browse all CWE-295

Provenance

Sources

OSV.devNVDFIRST.org (EPSS)

Last verifiedOct 24, 2026

CVE-2016-2402 — okhttp

EPSS Exploitation Probability

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

Description

Affected Packages

Affected Products

Detection & mitigation playbook

Detect

Fix

Workarounds

Frequently Asked Questions

Is CVE-2016-2402 in your dependencies?