CVE-2016-4656 — Iphone Os
HIGHCVE-2016-4656 is a high-severity (CVSS 7.8) Out-of-bounds Write vulnerability in apple iphone os. It is in CISA's Known Exploited Vulnerabilities catalog (added 2022-05-24) — treat it as actively exploited and patch now. A fix is available — see the affected versions and patch details below.
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.
Exploitation Status
Actively exploited in the wild
- Confirmed by CISA's Known Exploited Vulnerabilities catalog on 2022-05-24. Federal agencies were required to remediate by 2022-06-14.
- A successful exploit gives an attacker total control of the affected component, not partial access.
Exploitation and automatability from CISA (KEV catalog and SSVC triage) for CVE-2016-4656.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
CVE-2016-4656 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.
Where this sits among everything scored
Of 394,803 CVEs with a current EPSS score, this one falls in the 10–50% band (highlighted). Counts from FIRST.org, log-scaled.
Description
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.
Affected Products
iphone osappleResearch use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
WebKit - not_number defineProperties UAF (Metasploit)
by Metasploit · Jun 5, 2018
Detection & mitigation playbook
Vendor / applianceDetect
Inventory every apple iphone os deployment and check each version against the affected-products list above.
Fix
Apply the apple iphone os security patch or hotfix for CVE-2016-4656 on the affected version, following the vendor advisory for your exact build.
Workarounds
Constrain what reaches the vulnerable code: limit the size and shape of untrusted input, isolate the affected component in a sandboxed or least-privileged process, and enable the platform's memory-safety mitigations (ASLR, stack protector, hardened allocator) so an out-of-bounds access is more likely to fail closed than to be exploitable. Alongside that, restrict the management interface to trusted networks and apply the vendor's recommended configuration mitigations.
Frequently Asked Questions
Is CVE-2016-4656 being exploited in your environment?
Detect and block the exploit chain at execution, on systems you cannot patch yet.