Skip to content
Thoughtful, detailed coverage of everything Apple for 34 years
and the TidBITS Content Network for Apple professionals

Security Update 2021-004 Catalina and 2021-005 Mojave

Apple has released Security Update 2021-004 for macOS 10.15 Catalina and Security Update 2021-005 for 10.14 Mojave, patching 25 security vulnerabilities in Catalina and 19 vulnerabilities in Mojave. Both updates address a memory corruption issue in Bluetooth that could allow a malicious application to gain root privileges, resolve multiple memory corruption issues in WebKit that could allow arbitrary code execution via maliciously crafted Web content, and fix multiple issues with FontParser. If you notice any problems after updating, please let us know in the comments. (Free, various sizes, Catalina release notes and Mojave release notes, macOS 10.15.7 and 10.14.6)

Subscribe today so you don’t miss any TidBITS articles!

Every week you’ll get tech tips, in-depth reviews, and insightful news analysis for discerning Apple users. For over 33 years, we’ve published professional, member-supported tech journalism that makes you smarter.

Registration confirmation will be emailed to you.

This site is protected by reCAPTCHA. The Google Privacy Policy and Terms of Service apply.

Comments About Security Update 2021-004 Catalina and 2021-005 Mojave

Notable Replies

  1. Installed on Mid 2012 13’ MacBook pro now it appears bricked. Stuck on startup screen for more than 3 hours.

  2. I am sorry to hear about your MacBook Pro. I often worry when installing something.

    In this case, 2021-005 Mojave installed normally (by which I mean it was time-consuming and boring) on a 2014 iMac and a 2015 MacBook. As usual after a security update, macOS wanted to “set up” each user’s account, and it went for minutes with no indication that anything was happening. Both computers seem to be working normally. (I installed Safari 14.1.2 at the same time, but I usually use Firefox and so haven’t used the new version of Safari.)

  3. Any indication if these updates correct Kerberos problems with Active Directory joined Macs that started with updates 2021-004 (Mojave) and 2021-003 (Catalina)? Macs would become unresponsive if they were off the network and went to sleep after running the security update.
    Solutions were to install Mac OS 11, or restore from a backup done prior to running the respective updates (also do backup before updates, right) and turn off automatic updates. I would like to start applying the security updates on Macs in the office, but network is not ready for 11.

  4. Discussions earlier this week in the #Mojave MacAdmins channel appear to say yes. One IT tested it then the discussion turned to removing the workaround patches that many had deployed.

  5. Thank you. I tested a couple of workarounds - they didn’t work. I could not afford anymore time testing so just restored from backup and stopped all updates on the Macs on the network (that might be taken off the network for use at home).

  6. I started the 3 installers on a Mac mini (Late 2012), 10.14.6 , left them to run and went away for a couple of hours…came back to a blank black screen (no progress bar) which would not respond to keyboard or trackball.…forced shutdown with power button and restarted successfully. Evidently the updates had not been installed as a recheck of the Updates System Preference showed they were still available to be installed.

    I’m going to let sleeping dogs lie and not attempt to update. I wonder if the age of the Mac has something to do with the installation problem.

Join the discussion in the TidBITS Discourse forum


Avatar for ace Avatar for agen Avatar for alvarnell Avatar for johnbeare298 Avatar for Will_M Avatar for strangebeats Avatar for StephenGrady