Bug 2373616 (CVE-2022-50222) - CVE-2022-50222 kernel: tty: vt: initialize unicode screen buffer
Summary: CVE-2022-50222 kernel: tty: vt: initialize unicode screen buffer
Keywords:
Status: NEW
Alias: CVE-2022-50222
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Product Security DevOps Team
QA Contact:
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2025-06-18 12:10 UTC by OSIDB Bzimport
Modified: 2025-06-19 03:28 UTC (History)
4 users (show)

Fixed In Version:
Clone Of:
Environment:
Last Closed:
Embargoed:


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Description OSIDB Bzimport 2025-06-18 12:10:49 UTC
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;
  }
  ----------

Comment 1 Avinash Hanwate 2025-06-19 03:17:54 UTC
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2025061847-CVE-2022-50222-bb8e@gregkh/T


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