How severe is CVE-2016-4657?

CVE-2016-4657 has a CVSS score of 8.8/10, rated HIGH. Immediate patching is strongly recommended.

Which packages are affected by CVE-2016-4657?

Affected package information for CVE-2016-4657 is not yet fully mapped. Check the official advisory links for details.

How do I fix CVE-2016-4657?

No fixed version has been published for CVE-2016-4657 yet. Monitor the advisory for updates, apply mitigations recommended by the vendor, and use O3 Security to track when a fix becomes available in your stack.

Is CVE-2016-4657 actively exploited in the wild?

Yes. There are 15 known exploit references for CVE-2016-4657, including 2 documented proof-of-concept exploits on Exploit-DB and 10 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-2016-4657?

CVE-2016-4657 has an EPSS (Exploit Prediction Scoring System) score of 79.4%, placing it in the 99th 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. A score above 50% indicates significantly elevated exploitation risk — immediate patching is strongly recommended.

Is CVE-2016-4657 in the CISA Known Exploited Vulnerabilities catalog?

Yes. CVE-2016-4657 (Apple iOS Webkit Memory Corruption Vulnerability) was added to CISA's Known Exploited Vulnerabilities (KEV) catalog on 2022-05-24. CISA required all US federal civilian agencies to remediate this vulnerability by 2022-06-14. The required action was: Apply updates per vendor instructions. Being listed in the KEV catalog is the strongest possible confirmation of active exploitation — treat this as a critical priority.

What type of vulnerability is CVE-2016-4657?

CVE-2016-4657 is classified as Out-of-bounds Write (CWE-787). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

Which products and versions are affected by CVE-2016-4657?

CVE-2016-4657 affects apple iphone os. Check the affected-products list on this page against your deployed version to confirm exposure.

When was CVE-2016-4657 published, and has it been updated?

CVE-2016-4657 was published on August 25, 2016 and was last updated on April 21, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

CISA KEV·Added 2022-05-24 — agencies required to remediate by 2022-06-14

CVE-2016-4657

HIGH

WebKit in Apple iOS before 9.3.5 allows remote attackers to execute arbitrary code or cause a denial of service (memory corruption) via a crafted web site.

Published

Aug 25, 2016

Updated

Apr 21, 2026

Affected

0 pkgs

Patched

None yet

Exploits

15 known

EPSS Exploitation Probability

via FIRST.org ↗

79.4%probability of exploitation in next 30 days

Very High Risk99th percentile0.00%

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

Description

WebKit in Apple iOS before 9.3.5 allows remote attackers to execute arbitrary code or cause a denial of service (memory corruption) via a crafted web site.

Affected Products

1 product · 1 configurations

iphone osapple

< 9.3.5

range

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.

EDB-44213doshardware

Nintendo Switch - WebKit Code Execution (PoC)

by qwertyoruiop · Mar 12, 2017

Exploit-DB Source

EDB-44836remoteios✓ Verified

WebKit - not_number defineProperties UAF (Metasploit)

by Metasploit · Jun 5, 2018

Exploit-DB Source

Frequently Asked Questions

WebKit in Apple iOS before 9.3.5 allows remote attackers to execute arbitrary code or cause a denial of service (memory corruption) via a crafted web site.

O3 Security · Impact-Aware SCA

Is CVE-2016-4657 in your stack?

O3 detects CVE-2016-4657 across dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

Scan my stack How O3 SCA works

CVSS Score

8.8/10

CVSS v3 base score

Vector breakdown

AV:Attack Vector

Network

AC:Attack Complexity

Low

PR:Privileges Required

None

UI:User Interaction

Required

S:Scope

Unchanged

C:Confidentiality

High

I:Integrity

High

A:Availability

High

Raw vector

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

CWE Classification

CWE-787Out-of-bounds Write

Weaponization

No known public exploit tooling found.

Timeline

Disclosed

Aug 25, 2016

First exploit

Mar 12, 2017

KEV added

May 24, 2022

Last updated

Apr 21, 2026

Identifiers

CVE-2016-4657

References

Advisorylists.apple.com Advisorysecurityfocus.com Advisorysecuritytracker.com Advisorysupport.apple.com Advisorylists.apple.com Advisorysecurityfocus.com Advisorysecuritytracker.com Advisorysupport.apple.com Exploit / PoCexploit-db.com Exploit / PoCyoutube.com Exploit / PoCexploit-db.com Exploit / PoCyoutube.com Webblog.lookout.com Webblog.lookout.com Webcisa.gov

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