CVE-2024-50048

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Source
https://cve.org/CVERecord?id=CVE-2024-50048
Import Source
https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2024-50048.json
JSON Data
https://api.test.osv.dev/v1/vulns/CVE-2024-50048
Downstream
Related
Published
2024-10-21T19:39:45Z
Modified
2026-08-12T03:30:48Z
Summary
fbcon: Fix a NULL pointer dereference issue in fbcon_putcs
Details

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.

Database specific 
{
    "cna_assigner":  "Linux",
    "osv_generated_from":  "https://github.com/CVEProject/cvelistV5/tree/main/cves/2024/50xxx/CVE-2024-50048.json"
}
References

Affected packages

Git / git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git

Affected ranges

Type
GIT
Repo
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
Events
Introduced
b07db39584856e16814e2f065380e533a001535d
Fixed
8266ae6eafdcd5a3136592445ff4038bbc7ee80e
Fixed
f7fb5dda555344529ce584ff7a28b109528d2f1b
Fixed
e5c2dba62996a3a6eeb34bd248b90fc69c5a6a1b
Fixed
5b97eebcce1b4f3f07a71f635d6aa3af96c236e7

Database specific

source 
"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2024-50048.json"

Linux / Kernel

Package

Name
Kernel

Affected ranges

Type
ECOSYSTEM
Events
Introduced
5.19.0
Fixed
6.1.113
Type
ECOSYSTEM
Events
Introduced
6.2.0
Fixed
6.6.57
Type
ECOSYSTEM
Events
Introduced
6.7.0
Fixed
6.11.4

Database specific

source 
"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2024-50048.json"