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

Max Headroom 2025.05.12 2 min read

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.

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

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