Should you update to macOS Sequoia 15.7.9?
No: install macOS Sequoia 15.8.2 instead. macOS Sequoia 15.7.9 is a security update Apple released on 6 Aug 2026 for Mac. It fixes 1 security flaw.[1] One of them is already being used in attacks.
It has since been replaced by macOS Sequoia 15.8, released 14 Sep 2026, which includes all of its fixes. If you’re on an older version, install that instead.
Should you update?
No: install macOS Sequoia 15.8.2 instead. macOS Sequoia 15.8.2 came out on 26 Oct 2026 and includes every fix in macOS Sequoia 15.7.9, so there’s no reason to stop at this one. Software Update offers the newest version your Mac can run.
Is macOS Sequoia 15.7.9 still safe?
Not any more. The 3 updates since, up to macOS Sequoia 15.8.2, fix 378 security flaws that macOS Sequoia 15.7.9 doesn’t, and each became public the day its fix shipped. Installing it is safe: get it only from System Settings → General → Software Update, never from a link in an email, text or pop-up.
What it fixes
Apple lists 1 security flaw across 1 parts of macOS. For each, Apple says what an attacker could have done before the fix.[1]
| Part | Flaws | What an attacker could do |
|---|---|---|
| Screen Sharing | 1 | An attacker on the network may be able to authenticate to Screen Sharing without valid credentials |
Used in attacks
This fix closes a flaw that attackers were already using before the update came out, either on CISA’s list of flaws being used in attacks or in Apple’s own words.[2]
How to update, and how long it takes
It takes 15 to 45 minutes in all: a few minutes to download, then it prepares, installs and restarts, and you can’t use the Mac while it installs.
- Back up first if you can.iCloud backup or your computer. Updates rarely go wrong, but a backup makes it painless if one does.
- Open Apple menu → System Settings → General → Software Update.Your Mac shows the newest version it can run. Tap or click Update Now, or Upgrade Now for a new major version.
- Leave it plugged in.It downloads, prepares and restarts. Expect 15 to 45 minutes.
- Turn on automatic updates.In the same place, under Automatic Updates, turn on both downloading and installing security responses and updates.
To check it worked: Apple menu → About This Mac shows the macOS name and version. It should say Sequoia 15.8 or later.
Older devices
The same day, Apple released macOS Tahoe 26.6.1 (1 security flaw) and macOS Sonoma 14.8.9 (1 security flaw) for Macs that stay on an older version. Each fixes the same holes where they apply.
Sequoia 15.7.8 vs Sequoia 15.7.9
macOS Sequoia 15.7.8, released 27 Jul 2026, fixed 148 security flaws. macOS Sequoia 15.7.9 fixes 1 security flaw and includes the fixes before it, so going straight to Sequoia 15.7.9 gets you both.
- Before: macOS Sequoia 15.7.8, 27 Jul 2026, 148 security flaws
- After: macOS Sequoia 15.8, 14 Sep 2026, 180 security flaws
- macOS updates, every release and the latest version
- Updates, the latest version of everything HARD tracks
References
- ^ Apple. “About the security content of macOS Sequoia 15.7.9”, 6 Aug 2026.
- ^ Cybersecurity and Infrastructure Security Agency. “Known Exploited Vulnerabilities Catalog”.