CVE-2024-50048

MEDIUM EPSS 15.9%
Published Oct 21, 20241y ago · Modified Jun 17, 20261w ago
5.5 CVSS 3.1
Medium
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Published Oct 21, 2024 1y ago
Last Modified Jun 17, 2026 1w ago

Description

In the Linux kernel, the following vulnerability has been resolved: fbcon: Fix a NULL pointer dereference issue in fbcon_putcs syzbot has found a NULL pointer dereference bug in fbcon. Here is the simplified C reproducer: struct param { uint8_t type; struct tiocl_selection ts; }; int main() { struct fb_con2fbmap con2fb; struct param param; int fd = open("/dev/fb1", 0, 0); con2fb.console = 0x19; con2fb.framebuffer = 0; ioctl(fd, FBIOPUT_CON2FBMAP, &con2fb); param.type = 2; param.ts.xs = 0; param.ts.ys = 0; param.ts.xe = 0; param.ts.ye = 0; param.ts.sel_mode = 0; int fd1 = open("/dev/tty1", O_RDWR, 0); ioctl(fd1, TIOCLINUX, &param); con2fb.console = 1; con2fb.framebuffer = 0; ioctl(fd, FBIOPUT_CON2FBMAP, &con2fb); return 0; } After calling ioctl(fd1, TIOCLINUX, &param), the subsequent ioctl(fd, FBIOPUT_CON2FBMAP, &con2fb) causes the kernel to follow a different execution path: set_con2fb_map -> con2fb_init_display -> fbcon_set_disp -> redraw_screen -> hide_cursor -> clear_selection -> highlight -> invert_screen -> do_update_region -> fbcon_putcs -> ops->putcs Since ops->putcs is a NULL pointer, this leads to a kernel panic. To prevent this, we need to call set_blitting_type() within set_con2fb_map() to properly initialize ops->putcs.

CVSS Details

Base Score
5.5
Exploitability
1.8
Impact
3.6
Vector string
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Attack Vector Local
Attack Complexity Low
Privileges Required Low
User Interaction None
Scope Unchanged
Confidentiality None
Integrity None
Availability High

Threat Intelligence

EPSS Exploit Probability
15.9% percentile
Exploit & Patch Status
No Known Exploit
Patch Available

Weaknesses 1

CWE-476 NULL Pointer Dereference Memory Safety

Affected Products 3

VendorProductVersionRange
linuxlinux_kernel* <6.1.113
linuxlinux_kernel*≥6.2  –  <6.6.57
linuxlinux_kernel*≥6.7  –  <6.11.4

References 5

  • git.kernel.org https://git.kernel.org/stable/c/5b97eebcce1b4f3f07a71f635d6aa3af96c236e7
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/8266ae6eafdcd5a3136592445ff4038bbc7ee80e
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/e5c2dba62996a3a6eeb34bd248b90fc69c5a6a1b
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/f7fb5dda555344529ce584ff7a28b109528d2f1b
    Patch
  • lists.debian.org https://lists.debian.org/debian-lts-announce/2025/01/msg00001.html

Remediation

  • git.kernel.org https://git.kernel.org/stable/c/5b97eebcce1b4f3f07a71f635d6aa3af96c236e7
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/8266ae6eafdcd5a3136592445ff4038bbc7ee80e
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/e5c2dba62996a3a6eeb34bd248b90fc69c5a6a1b
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/f7fb5dda555344529ce584ff7a28b109528d2f1b
    Patch