CVE-2025-40323 Affecting libperf package, versions *


Severity

Recommended
medium

Based on CentOS security rating.

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  • Snyk IDSNYK-CENTOS10-LIBPERF-14230712
  • published9 Dec 2025
  • disclosed8 Dec 2025

Introduced: 8 Dec 2025

NewCVE-2025-40323  (opens in a new tab)

How to fix?

There is no fixed version for Centos:10 libperf.

NVD Description

Note: Versions mentioned in the description apply only to the upstream libperf package and not the libperf package as distributed by Centos. See How to fix? for Centos:10 relevant fixed versions and status.

In the Linux kernel, the following vulnerability has been resolved:

fbcon: Set fb_display[i]->mode to NULL when the mode is released

Recently, we discovered the following issue through syzkaller:

BUG: KASAN: slab-use-after-free in fb_mode_is_equal+0x285/0x2f0 Read of size 4 at addr ff11000001b3c69c by task syz.xxx ... Call Trace: <TASK> dump_stack_lvl+0xab/0xe0 print_address_description.constprop.0+0x2c/0x390 print_report+0xb9/0x280 kasan_report+0xb8/0xf0 fb_mode_is_equal+0x285/0x2f0 fbcon_mode_deleted+0x129/0x180 fb_set_var+0xe7f/0x11d0 do_fb_ioctl+0x6a0/0x750 fb_ioctl+0xe0/0x140 __x64_sys_ioctl+0x193/0x210 do_syscall_64+0x5f/0x9c0 entry_SYSCALL_64_after_hwframe+0x76/0x7e

Based on experimentation and analysis, during framebuffer unregistration, only the memory of fb_info->modelist is freed, without setting the corresponding fb_display[i]->mode to NULL for the freed modes. This leads to UAF issues during subsequent accesses. Here's an example of reproduction steps:

  1. With /dev/fb0 already registered in the system, load a kernel module to register a new device /dev/fb1;
  2. Set fb1's mode to the global fb_display[] array (via FBIOPUT_CON2FBMAP);
  3. Switch console from fb to VGA (to allow normal rmmod of the ko);
  4. Unload the kernel module, at this point fb1's modelist is freed, leaving a wild pointer in fb_display[];
  5. Trigger the bug via system calls through fb0 attempting to delete a mode from fb0.

Add a check in do_unregister_framebuffer(): if the mode to be freed exists in fb_display[], set the corresponding mode pointer to NULL.

CVSS Base Scores

version 3.1