CVE-2022-50222: tty: vt: initialize unicode screen buffer

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2025-06-18 · updated 2026-06-17

Description

In the Linux kernel, the following vulnerability has been resolved: tty: vt: initialize unicode screen buffer syzbot reports kernel infoleak at vcs_read() [1], for buffer can be read immediately after resize operation. Initialize buffer using kzalloc(). ---------- #include <fcntl.h> #include <unistd.h> #include <sys/ioctl.h> #include <linux/fb.h> int main(int argc, char *argv[]) { struct fb_var_screeninfo var = { }; const int fb_fd = open("/dev/fb0", 3); ioctl(fb_fd, FBIOGET_VSCREENINFO, &var); var.yres = 0x21; ioctl(fb_fd, FBIOPUT_VSCREENINFO, &var); return read(open("/dev/vcsu", O_RDONLY), &var, sizeof(var)) == -1; } ----------

Affected products

Linux kernel: from 4.19 before 4.19.256; from 4.20 before 5.4.211; from 5.5 before 5.10.137; from 5.11 before 5.15.61; from 5.16 before 5.18.18; from 5.19 before 5.19.2 — fixed in 4.19.256, 5.10.137, 5.15.61, 5.18.18, 5.19.2, 5.4.211

How to fix

Upgrade to a fixed version: Linux kernel 4.19.256, 5.10.137, 5.15.61, 5.18.18. Check the vendor advisory for mitigations.

References

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