cve/2025/CVE-2025-38215.md

### [CVE-2025-38215](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2025-38215)
![](https://img.shields.io/static/v1?label=Product&message=Linux&color=blue)
![](https://img.shields.io/static/v1?label=Version&message=&color=brightgreen)
![](https://img.shields.io/static/v1?label=Version&message=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2%20&color=brightgreen)
![](https://img.shields.io/static/v1?label=Version&message=2.6.12%20&color=brightgreen)
![](https://img.shields.io/static/v1?label=Vulnerability&message=n%2Fa&color=blue)

### Description

In the Linux kernel, the following vulnerability has been resolved:fbdev: Fix do_register_framebuffer to prevent null-ptr-deref in fb_videomode_to_varIf fb_add_videomode() in do_register_framebuffer() fails to allocatememory for fb_videomode, it will later lead to a null-ptr dereference infb_videomode_to_var(), as the fb_info is registered while not having themode in modelist that is expected to be there, i.e. the one that isdescribed in fb_info->var.================================================================general protection fault, probably for non-canonical address 0xdffffc0000000001: 0000 [#1] PREEMPT SMP KASAN NOPTIKASAN: null-ptr-deref in range [0x0000000000000008-0x000000000000000f]CPU: 1 PID: 30371 Comm: syz-executor.1 Not tainted 5.10.226-syzkaller #0Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014RIP: 0010:fb_videomode_to_var+0x24/0x610 drivers/video/fbdev/core/modedb.c:901Call Trace: display_to_var+0x3a/0x7c0 drivers/video/fbdev/core/fbcon.c:929 fbcon_resize+0x3e2/0x8f0 drivers/video/fbdev/core/fbcon.c:2071 resize_screen drivers/tty/vt/vt.c:1176 [inline] vc_do_resize+0x53a/0x1170 drivers/tty/vt/vt.c:1263 fbcon_modechanged+0x3ac/0x6e0 drivers/video/fbdev/core/fbcon.c:2720 fbcon_update_vcs+0x43/0x60 drivers/video/fbdev/core/fbcon.c:2776 do_fb_ioctl+0x6d2/0x740 drivers/video/fbdev/core/fbmem.c:1128 fb_ioctl+0xe7/0x150 drivers/video/fbdev/core/fbmem.c:1203 vfs_ioctl fs/ioctl.c:48 [inline] __do_sys_ioctl fs/ioctl.c:753 [inline] __se_sys_ioctl fs/ioctl.c:739 [inline] __x64_sys_ioctl+0x19a/0x210 fs/ioctl.c:739 do_syscall_64+0x33/0x40 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x67/0xd1================================================================Even though fbcon_init() checks beforehand if fb_match_mode() invar_to_display() fails, it can not prevent the panic because fbcon_init()does not return error code. Considering this and the comment in the codeabout fb_match_mode() returning NULL - "This should not happen" - it isbetter to prevent registering the fb_info if its mode was not setsuccessfully. Also move fb_add_videomode() closer to the beginning ofdo_register_framebuffer() to avoid having to do the cleanup on fail.Found by Linux Verification Center (linuxtesting.org) with Syzkaller.

### POC

#### Reference
No PoCs from references.

#### Github
- https://github.com/w4zu/Debian_security