PatchSiren cyber security CVE debrief
CVE-2016-4671 Apple CVE debrief
CVE-2016-4671 describes a memory-corruption issue in Apple’s ImageIO component on macOS. The problem is associated with crafted PDF content and is described as allowing remote attackers to execute arbitrary code or cause a denial of service through an out-of-bounds write and application crash. NVD lists affected macOS versions through 10.12.0, matching the narrative that systems before 10.12.1 are impacted.
- Vendor
- Apple
- Product
- CVE-2016-4671
- CVSS
- HIGH 7.8
- CISA KEV
- Not listed in stored evidence
- Original CVE published
- 2017-02-20
- Original CVE updated
- 2026-05-13
- Advisory published
- 2017-02-20
- Advisory updated
- 2026-05-13
Who should care
Mac administrators, endpoint security teams, and users running macOS 10.12.0 or earlier should care most. Systems that process untrusted PDFs or receive documents from external sources are the highest-priority review targets.
Technical summary
NVD classifies the weakness as CWE-787 (out-of-bounds write). The affected component is ImageIO, and the attack surface is tied to crafted PDF input. The CVSS vector in NVD is CVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H, which indicates user interaction is required and that successful exploitation could have high impact on confidentiality, integrity, and availability. The narrative description emphasizes remote delivery via PDF, while the CVSS vector reflects that the vulnerable code path is reached only after a user opens or otherwise processes the file.
Defensive priority
High. The issue can lead to code execution, the impacted versions are specific and older, and the vector indicates user interaction with potentially high impact.
Recommended defensive actions
- Upgrade affected Macs to macOS 10.12.1 or later, or the newest supported release available for the device.
- Confirm whether any systems remain on macOS 10.12.0 or earlier and prioritize those endpoints for patching.
- Treat untrusted PDFs as higher risk on unpatched systems and limit exposure to external document sources until remediation is complete.
- Use endpoint inventory and vulnerability scanning to verify that the ImageIO-related fix is present across the fleet.
- For any business-critical legacy Macs that cannot be upgraded, apply compensating controls such as stricter document handling and isolation until they can be retired or updated.
Evidence notes
NVD’s record identifies Apple macOS as the affected platform, with vulnerability coverage through 10.12.0 and CWE-787 as the weakness type. The supplied description states the issue involves ImageIO and crafted PDF files, with outcomes including arbitrary code execution or denial of service via out-of-bounds write and crash. Apple’s support advisory HT207275 is listed as a reference in the NVD record, providing an official vendor link associated with the fix.
Official resources
The CVE was published in NVD on 2017-02-20. Apple’s advisory HT207275 is referenced in the NVD record. Use the CVE publication timestamp as the issue-date anchor; do not infer any later publication or review time as the original disclosure.