CVE-2017-11121: Apple iPhone OS

Critical severity, CVSS 9.8. EPSS: 2.8% chance of exploitation in the next 30 days.

On Broadcom BCM4355C0 Wi-Fi chips 9.44.78.27.0.1.56 and other chips, properly crafted malicious over-the-air Fast Transition frames can potentially trigger internal Wi-Fi firmware heap and/or stack overflows, leading to denial of service or other effects, aka B-V2017061205.

Affected products

• Apple iPhone OS: before 11.0 (fixed in 11.0)
• Apple tvOS: before 11.0 (fixed in 11.0)
• Broadcom BCM4355C0 Firmware: version 9.44.78.27.0.1.56 only

Published 2017-09-28. Last modified 2026-06-17.