CVE-2023-42916
CVE-2023-42916 is a security flaw in Apple devices, the software on Apple’s iPhones, iPads and Macs. Attackers can corrupt memory in Apple devices, which they use to take it over. The US Cybersecurity and Infrastructure Security Agency (CISA) added it to its catalog of flaws known to be used in attacks on 4 Dec 2023.[1]
Apple devices is in things households have, such as phones, computers, browsers and everyday apps, so the fix matters at home as much as at work. Fixed in version 17.1, 14.1, 17.1.2 and 14.1.2.
Description
CISA calls it a webKit out-of-bounds read in Apple Multiple Products. In its words: “Apple iOS, iPadOS, macOS, and Safari WebKit contain an out-of-bounds read vulnerability that may disclose sensitive information when processing maliciously crafted web content. This vulnerability could impact HTML parsers that use WebKit, including but not limited to Apple Safari and non-Apple products which rely on WebKit for HTML processing.”[1]
The underlying weakness is out-of-bounds read (CWE-125), in MITRE’s list of common software weaknesses.[2]
It scores 6.5 out of 10 on the Common Vulnerability Scoring System, which rates it medium, scored by NVD using CVSS 3.1.[2]
Affected versions
NVD’s record lists these fixed versions: in each line, everything before the version shown is affected.[2]
| Product | Fixed in |
|---|---|
| Safari | 17.1 |
| macOS | 14.1 |
| iOS and iPadOS | 17.1 |
| iphone_os | 17.1.2 |
| ipados | 17.1.2 |
| macos | 14.1.2 |
| safari | 17.1.2 |
Every device with Apple devices needs the update.
Exploitation
CISA added it to its catalog of known exploited vulnerabilities on 4 Dec 2023, 4 days after it was made public. CISA lists a flaw only when it has reliable evidence of it being exploited, and gave US federal agencies until 25 Dec 2023 to fix it.[1]
FIRST’s Exploit Prediction Scoring System, which estimates how likely a flaw is to be used in attacks in the next 30 days from what it sees across the internet, puts it at 18%. That’s in the top 3% of the flaws it scores.[4]
CISA assesses it as not automatable: each attack takes some work.
CISA doesn’t say who was attacked, or how.
Fix
Apple has published a fix or advice.[3] CISA’s required action: “Apply remediations or mitigations per vendor instructions or discontinue use of the product if remediation or mitigations are unavailable.”[1]
- Update Apple devices now.On iPhone and iPad: Settings, General, Software Update. On a Mac: System Settings, General, Software Update. Install it on every Apple device in the house. Then turn on automatic updates, so the next fix arrives on its own.
- Check you’re on 17.1 or later.Fixed in version 17.1, 14.1, 17.1.2 and 14.1.2. Anything older is what attackers are going after.
- If there’s no update, stop using it.CISA’s advice when a flaw being used in attacks has no fix is to stop using the product until it does.
Timeline
| Date | Event |
|---|---|
| The flaw is made public in the National Vulnerability Database, with a severity score of 6.5.[2] | |
| CISA adds it to its catalog of flaws known to be used in attacks.[1] | |
| CISA’s deadline for US government agencies to fix it.[1] | |
| FIRST puts the odds of it being used in attacks in the next 30 days at 18%.[4] |
See also
Other Apple devices flaws
- CVE-2026-86950: out-of-bounds write ·
- CVE-2025-43520: classic buffer overflow ·
- CVE-2025-43510: improper locking ·
- CVE-2025-31277: buffer overflow ·
- CVE-2023-43000: use-after-free ·
- CVE-2021-30952: integer overflow or wraparound ·
Other out-of-bounds read flaws
- CVE-2023-36424, Microsoft Windows: out-of-bounds read ·
- CVE-2026-3055, Citrix NetScaler: out-of-bounds read ·
- CVE-2025-5777, Citrix NetScaler ADC and Gateway: out-of-bounds read ·
- CVE-2025-5419, Chrome and other Chromium browsers: out-of-bounds read and write ·
- CVE-2024-53150, Linux Kernel: out-of-bounds read ·
Added the same day
- CVE-2023-42917, Apple devices: webKit memory corruption ·
Every Apple flaw on CISA’s list · Everything added in December 2023
References
- ^ Cybersecurity and Infrastructure Security Agency. “Apple Multiple Products WebKit Out-of-Bounds Read Vulnerability”. Known Exploited Vulnerabilities Catalog, added 4 Dec 2023.
- ^ National Institute of Standards and Technology. “CVE-2023-42916 Detail”. National Vulnerability Database, published 30 Nov 2023.
- ^ Apple. Advisories and fixes: support.apple.com, support.apple.com, support.apple.com, support.apple.com, support.apple.com, and 1 more on NVD’s record.
- ^ FIRST. “Exploit Prediction Scoring System”. EPSS 0.178, percentile 97.2, 31 Oct 2026.
- CVE Program. “CVE-2023-42916”. The official CVE record.
This article is built from CISA’s catalog (version 2026.10.30), NVD’s record and FIRST’s scores, kept in HARD’s database and checked every morning. The plain English is HARD’s.