CVE-2024-49924: Debian Linux

High severity, CVSS 7.8. EPSS: 0.2% chance of exploitation in the next 30 days.

In the Linux kernel, the following vulnerability has been resolved: fbdev: pxafb: Fix possible use after free in pxafb_task() In the pxafb_probe function, it calls the pxafb_init_fbinfo function, after which &fbi->task is associated with pxafb_task. Moreover, within this pxafb_init_fbinfo function, the pxafb_blank function within the &pxafb_ops struct is capable of scheduling work. If we remove the module which will call pxafb_remove to make cleanup, it will call unregister_framebuffer function which can call do_unregister_framebuffer to free fbi->fb through put_fb_info(fb_info), while the work mentioned above will be used. The sequence of operations that may lead to a UAF bug is as follows: CPU0 CPU1 | pxafb_task pxafb_remove | unregister_framebuffer(info) | do_unregister_framebuffer(fb_info) | put_fb_info(fb_info) | // free fbi->fb | set_ctrlr_state(fbi, state) | __pxafb_lcd_power(fbi, 0) | fbi->lcd_power(on, &fbi->fb.var) | //use fbi->fb Fix it by ensuring that the work is canceled before proceeding with the cleanup in pxafb_remove. Note that only root user can remove the driver at runtime.

Affected products

• Debian Debian Linux: version 11.0 only
• Linux Linux Kernel: from 2.6.27, before 4.19.323 (fixed in 4.19.323); from 4.20, before 5.4.285 (fixed in 5.4.285); from 5.5, before 5.10.227 (fixed in 5.10.227); from 5.11, before 5.15.168 (fixed in 5.15.168); from 5.16, before 6.1.113 (fixed in 6.1.113); from 6.2, before 6.6.55 (fixed in 6.6.55); …

Published 2024-10-21. Last modified 2026-08-04.