CVE-2016-4656

Exp

The kernel in Apple iOS before 9.3.5 allows attackers to execute arbitrary code in a privileged context or cause a denial of service (memory corruption) via a crafted app.

Published: 2016-08-25 Last update: 2026-04-21 Assigner: [email protected] Source: [email protected]
NVD Status：Analyzed，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2016-4656 is rated Critical Active Threat (89.3/100): CVSS High severity, with high exploitation likelihood (EPSS 65.33%, 99th percentile). CISA KEV confirms active exploitation (added 2022-05-24) affecting Apple / iOS. a weakness (CWE-787) Unauthenticated remote administrative access may be possible. The CISA remediation deadline has passed—treat as an emergency patch priority.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

CISA KEV Record for CVE-2016-4656

Name: Apple iOS Memory Corruption Vulnerability · CISA KEV detail

Exploit added: 2022-05-24

Action due: 2022-06-14

Required action: Apply updates per vendor instructions.

Public exploit references (Exploit-DB) for CVE-2016-4656

EDB-ID Source Kind Published Link
44836 exploit_db edb 2018-06-05 Exploit-DB ↗
— nvd_ref exploit_tag Exploit-DB ↗

Exploit prediction scoring system (EPSS) score for CVE-2016-4656

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-05-13 66.74% 65.33% -1.41%
2 2026-03-01 67.91% 66.74% -1.17%
3 2026-02-08 — 67.91% —

Full EPSS history (31 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2016-4656

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.8 3.1 HIGH
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H Click to expand
Attack vector (AV:L)
They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 1.8 5.9 [email protected]
7.8 3.1 HIGH
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H Click to expand
Attack vector (AV:L)
They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 1.8 5.9 134c704f-9b21-4f2e-91b3-4a467353bcc0
9.3 2.0 HIGH
AV:N/AC:M/Au:N/C:C/I:C/A:C Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:M)
Exploitation needs some favorable conditions, but not exceptional ones.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:C)
Complete confidentiality impact.
Integrity impact (I:C)
Complete integrity impact.
Availability impact (A:C)
Complete availability impact.
 8.6 10.0 [email protected]

Weakness enumeration for CVE-2016-4656

Affected software / configurations for CVE-2016-4656

Vendor Product Version Raw CPE
apple iphone_os < 9.3.5 cpe:2.3:o:apple:iphone_os:*:*:*:*:*:*:*:*

References for CVE-2016-4656

URL Tags
http://lists.apple.com/archives/security-announce/2016/Aug/msg00000.html Mailing List Vendor Advisory Broken Link
http://www.securityfocus.com/bid/92652 Broken Link Third Party Advisory VDB Entry
http://www.securitytracker.com/id/1036694 Broken Link Third Party Advisory VDB Entry
https://blog.lookout.com/blog/2016/08/25/trident-pegasus/ Broken Link
https://support.apple.com/HT207107 Release Notes Vendor Advisory
https://www.exploit-db.com/exploits/44836/ Exploit Third Party Advisory VDB Entry
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2016-4656 US Government Resource
cvelogic Threat Intelligence