Apple's C1 Modem Gets First Security Update in iOS 18.5

The iOS 18.5 update that Apple released today includes a security fix for the iPhone 16e's C1 modem, which is the first Apple-designed modem.

Apple iPhone 16e C1 Feature
According to Apple's security support document for iOS 18.5, there's a fix for a vulnerability with the C1 modem. Apple says that it addressed a baseband security flaw that could allow an attacker "in a privileged network position" to intercept network traffic. Basically, a hacker that had access to cellular network infrastructure could potentially exploit the vulnerability for surveillance or to employ a man-in-the-middle attack.

The C1's baseband is used for signal processing, so it encodes and decodes data for communication between devices and networks, and processes calls, texts, and data connections. Apple addressed the vulnerability with improved state management, which could mean new validation checks to prevent attackers from exploiting weaknesses between operational states.

Apple released the ‌iPhone 16e‌ earlier this year, and today's security update is notable because it marks the first security flaw discovered and addressed in the C1 modem.

iOS 18.5 also includes several other security fixes for vulnerabilities with image processing, call history, Bluetooth, file parsing, FaceTime, Notes, ProRes, WebKit, and more. None of the vulnerabilities fixed today were known to have been actively exploited, but it's still a good idea to update right away.

Related Roundup: iPhone 16e
Buyer's Guide: iPhone 16e (Buy Now)

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Top Rated Comments

mk313 Avatar
2 hours ago at 12:26 pm
I'm a little surprised at how well the Apple Designed modems appear to be working. When Apple moved to the Intel Modems, there was a lot of pushback on the performance relative to the Qualcomm ones. It seems like people are satisfied with the Apple designed ones (for the most part) which is hopefully good news for the future.
Score: 2 Votes (Like | Disagree)
TechTexan Avatar
2 hours ago at 12:39 pm

I'm a little surprised at how well the Apple Designed modems appear to be working. When Apple moved to the Intel Modems, there was a lot of pushback on the performance relative to the Qualcomm ones. It seems like people are satisfied with the Apple designed ones (for the most part) which is hopefully good news for the future.
I haven’t had any issues with mine, works the same if not better then my last phone.
Score: 2 Votes (Like | Disagree)
Danilamak Avatar
2 hours ago at 12:14 pm

The above is useful information for the main news article.
I always wonder this vulnerabilities new for 18 Os or that means they persists in all older versions?
Score: 2 Votes (Like | Disagree)
BigBlur Avatar
2 hours ago at 12:34 pm

I always wonder this vulnerabilities new for 18 Os or that means they persists in all older versions?
I wonder when vulnerabilities were introduced too, but older versions are usually patched as well. There were updates to macOS Sonoma, Ventura, and iPadOS 17 today. In March 2025, even iOS/iPadOS 16 and 15 got security updates, which goes way back to the iPhone 6S and iPad Air 2!

https://support.apple.com/en-us/100100
Score: 1 Votes (Like | Disagree)
Ceviche Lover Avatar
2 hours ago at 12:44 pm
After updating to this on my 16E, my cell signal keeps going into SOS every 15 minutes.
Score: 1 Votes (Like | Disagree)
I7guy Avatar
3 hours ago at 11:15 am

('https://www.macrumors.com/2025/05/12/apple-ios-18-5-c1-security-fix/')

[…]

iOS 18.5 also includes several other security fixes for vulnerabilities with image processing, call history, Bluetooth, file parsing, FaceTime, Notes, ProRes, WebKit, and more. None of the vulnerabilities fixed today were known to have been actively exploited, but it's still a good idea to update right away.

Article Link: Apple's C1 Modem Gets First Security Update in iOS 18.5 ('https://www.macrumors.com/2025/05/12/apple-ios-18-5-c1-security-fix/')
The above is useful information for the main news article.
Score: 1 Votes (Like | Disagree)