CVE-2026-46065: fbdev: defio: Disconnect deferred I/O from the lifetime of struct fb_info

Severity: high (CVSS 7.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.1% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-05-27 · updated 2026-10-19
Weakness: CWE-401

Description

In the Linux kernel, the following vulnerability has been resolved: fbdev: defio: Disconnect deferred I/O from the lifetime of struct fb_info Hold state of deferred I/O in struct fb_deferred_io_state. Allocate an instance as part of initializing deferred I/O and remove it only after the final mapping has been closed. If the fb_info and the contained deferred I/O meanwhile goes away, clear struct fb_deferred_io_state.info to invalidate the mapping. Any access will then result in a SIGBUS signal. Fixes a long-standing problem, where a device hot-unplug happens while user space still has an active mapping of the graphics memory. The hot- unplug frees the instance of struct fb_info. Accessing the memory will operate on undefined state.

Affected products

Linux kernel: from 2.6.22 before 5.15.210; from 5.16 before 6.1.176; from 6.2 before 6.6.140; from 6.7 before 6.12.88; from 6.13 before 6.18.30; from 6.19 before 7.0.4 — fixed in 5.15.210, 6.1.176, 6.12.88, 6.18.30, 6.6.140, 7.0.4

How to fix

Upgrade to a fixed version: Linux kernel 5.15.210, 6.1.176, 6.12.88, 6.18.30. Check the vendor advisory for mitigations.

References

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