Update Oct. 01, 2025: This article, originally published on Sept.30, has been updated to include details of bugs fixed in iOS 26.0.1 and adds expert comments about the iPhone updates.
Apple has issued iOS 26.0.1 and iOS 18.7.1, along with a warning to update your iPhone now. That’s because both iOS 26.0.1 and iOS 18.7.1 address a single security vulnerability in the iPhone maker’s operating system.
Apple doesn’t give much detail about what’s fixed in iOS 26.0.1 and iOS 18.7.1, to allow as many iPhone users as possible to update before attackers can get hold of the information.
However, iOS 26.0.1 and iOS 18.7.1 both fix the same security flaw in FontParser — a part of Apple’s operating system that processes font files — which could see unexpected app termination or corrupted process memory, if an iPhone user processes a maliciously crafted font. Tracked as CVE-2025-43400, the out-of-bounds write issue was addressed with improved bounds checking, according to Apple’s support page.
“The flaw could be triggered by a malicious font delivered via a document, email attachment, or web content, and may lead to unexpected application termination or memory corruption,” says Adam Boynton, senior security strategy manager EMEIA at cybersecurity outfit Jamf.
On its own, the vulnerability fixed in iOS 26.0.1 and iOS 18.7.1 does appear to “have a relatively low risk,” says Sean Wright, head of application security at Featurespace.
However, he warns that memory corruption “could potentially lead to more severe exploits such as code execution or privilege escalation.”
iOS 26.0.1 Fixes Bugs In the iOS 26 Update
When a new iPhone software is released, it will inevitably include bugs. However, those who already updated to iOS 26 will find many of the issues are fixed in the latest iOS 26.0.1 update. The iOS 26.0.1 upgrade apparently squashes bugs including issues with the iPhone’s Wi-Fi impacting iPhone 17 models.
Meanwhile, a small number of iPhone users may be unable to connect to a cellular network after updating to iOS 26, Apple said, adding that this should now be fixed.
Another bug addressed is a problem with photos taken under certain lighting conditions with iPhone 17, iPhone Air and iPhone 17 Pro models, which could include “unexpected artifacts,” Apple said.
Another bug fixed saw app icons appearing blank after adding a custom tint.
The iOS 26.0.1 update squashes a bug that could see VoiceOver become disabled for some users after updating to iOS 26.
Apple says that the macOS 26.0.1 update includes non-specific bug fixes and also addresses a problem that was keeping some users of this year’s high-end M3 Ultra Mac Studio from installing the update, according to tech site Ars Technica. The tvOS update fixes a problem that could cause audio to desync from video in some apps.
Many iPhone users who have already updated to iOS 26 expressed relief about the release of iOS 26.0.1. On a thread on Reddit, one user said: “I can say for sure that overall performance is a ton better and my keyboard lag is gone! So far not stuttering either.”
Others questioned whether all the bugs were fixed in iOS 26.0.1. “By the amount of bugs in iOS 26, I doubt they can even fit every bug fix into one update,” one person posted on Reddit. “I’d guess it takes at least two more to make it run somewhat decent.”
Apple is releasing iOS 26.1 soon, so hopefully there will be more bug fixes coming.
Why You Should Update To iOS 26.0.1 Or iOS 18.7.1 Now
The single issue patched in iOS 26.0.1 and iOS 18.7.1 has not been used in real-life attacks yet. But it’s still a good idea to update now — especially if you want to fix any bugs in iOS 26.
Boynton says the issue “has the potential to cause service disruptions or undermine system stability.”
With this in mind, he “strongly recommends updating to iOS 26.0.1 at your earliest convenience.”
But at the moment, you can still choose which iPhone upgrade to apply.
iOS 26.0.1 is available for iPhone 11 and later, iPad Pro 12.9-inch 3rd generation and later, iPad Pro 11-inch 1st generation and later, iPad Air 3rd generation and later, iPad 8th generation and later, and iPad mini 5th generation and later.
Meanwhile, iOS 18.7.1 is available for iPhone XS and later, iPad Pro 13-inch, iPad Pro 12.9-inch 3rd generation and later, iPad Pro 11-inch 1st generation and later, iPad Air 3rd generation and later, iPad 7th generation and later, and iPad mini 5th generation and later.
So, what are you waiting for? Go to your Settings > General > Software Update and download and install iOS 26.0.1 or iOS 18.7.1 now.