Apple Addresses Meltdown and Spectre in macOS Sierra and OS X El Capitan With New Security Update
Along with macOS High Sierra 10.13.3, Apple this morning released two new security updates that are designed to address the Meltdown and Spectre vulnerabilities on machines that continue to run macOS Sierra and OS X El Capitan.
As outlined in Apple's security support document, Security Update 2018-001 available for macOS Sierra 10.12.6 and OS X El Capitan 10.11.6 offers several mitigations for both Meltdown and Spectre, along with fixes for other security issues, and the updates should be installed immediately.

Apple addressed the Meltdown and Spectre vulnerabilities in macOS High Sierra with the release of macOS High Sierra 10.13.2, but older machines were left unprotected. Apple initially said a prior security update included fixes for the two older operating systems, but that information was later retracted.
Spectre and Meltdown are two hardware-based vulnerabilities that impact nearly all modern processors. Apple in early January confirmed that all of its Mac and iOS devices were impacted, but Meltdown mitigations were introduced ahead of when the vulnerabilities came to light in iOS 11.2 and macOS 10.13.2, and Spectre was addressed through Safari updates in iOS 11.2.2 and a macOS 10.13.2 Supplemental Update.
Spectre and Meltdown take advantage of the speculative execution mechanism of a CPU. As these use hardware-based flaws, operating system manufacturers are required to implement software workarounds. These software workarounds can impact processor performance, but according to Apple, the Meltdown fix has no measurable performance reduction across several benchmarks.
The Spectre Safari mitigations have "no measurable impact" on Speedometer and ARES-6 tests, and an impact of less than 2.5% on the JetStream benchmark.
Many PCs with Intel processors have been facing serious issues following the installation of patches with fixes for Meltdown and Spectre, but these problems do not appear to impact Apple's machines.
Popular Stories
Apple may have canceled the super scratch resistant anti-reflective display coating that it planned to use for the iPhone 17 Pro models, according to a source with reliable information that spoke to MacRumors.
Last spring, Weibo leaker Instant Digital suggested Apple was working on a new anti-reflective display layer that was more scratch resistant than the Ceramic Shield. We haven't heard...
This week marks the 10th anniversary of the Apple Watch, which launched on April 24, 2015. Yesterday, we recapped features rumored for the Apple Watch Series 11, but since 2015, the Apple Watch has also branched out into the Apple Watch Ultra and the Apple Watch SE, so we thought we'd take a look at what's next for those product lines, too.
2025 Apple Watch Ultra 3
Apple didn't update the...
Apple has completed Engineering Validation Testing (EVT) for at least one iPhone 17 model, according to a paywalled preview of an upcoming DigiTimes report.
iPhone 17 Air mockup based on rumored design
The EVT stage involves Apple testing iPhone 17 prototypes to ensure the hardware works as expected. There are still DVT (Design Validation Test) and PVT (Production Validation Test) stages to...
Apple will likely manufacture its 20th anniversary iPhone models in China, despite broader efforts to shift production to India, according to Bloomberg's Mark Gurman.
In 2027, Apple is planning a "major shake-up" for the iPhone lineup to mark two decades since the original model launched. Gurman's previous reporting indicates the company will introduce a foldable iPhone alongside a "bold"...
While the so-called "iPhone 17 Air" is not expected to launch until September, there are already plenty of rumors about the ultra-thin device.
Overall, the iPhone 17 Air sounds like a mixed bag. While the device is expected to have an impressively thin and light design, rumors indicate it will have some compromises compared to iPhone 17 Pro models, including only a single rear camera, a...
While the iPhone 17 Pro and iPhone 17 Pro Max are not expected to launch until September, there are already plenty of rumors about the devices.
Below, we recap key changes rumored for the iPhone 17 Pro models as of April 2025:
Aluminum frame: iPhone 17 Pro models are rumored to have an aluminum frame, whereas the iPhone 15 Pro and iPhone 16 Pro models have a titanium frame, and the iPhone ...
Apple is preparing to launch a dramatically thinner iPhone this September, and if recent leaks are anything to go by, the so-called iPhone 17 Air could boast one of the most radical design shifts in recent years.
iPhone 17 Air dummy model alongside iPhone 16 Pro (credit: AppleTrack)
At just 5.5mm thick (excluding a slightly raised camera bump), the 6.6-inch iPhone 17 Air is expected to become ...