CVE-2025-38214fbdev: Fix fb_set_var to prevent null-ptr-deref in fb_videomode_to_var
Updated under an hour ago ()
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In the Linux kernel, the following vulnerability has been resolved: fbdev: Fix fb_set_var to prevent null-ptr-deref in fb_videomode_to_var If fb_add_videomode() in fb_set_var() fails to allocate memory for fb_videomode, later it may lead to a null-ptr dereference in fb_videomode_to_var(), as the fb_info is registered while not having the mode in modelist that is expected to be there, i.e. the one that is described in fb_info->var. ================================================================ general protection fault, probably for non-canonical address 0xdffffc0000000001: 0000 [#1] PREEMPT SMP KASAN NOPTI KASAN: null-ptr-deref in range [0x0000000000000008-0x000000000000000f] CPU: 1 PID: 30371 Comm: syz-executor.1 Not tainted 5.10.226-syzkaller #0 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014 RIP: 0010:fb_videomode_to_var+0x24/0x610 drivers/video/fbdev/core/modedb.c:901 Call 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 ================================================================ The reason is that fb_info->var is being modified in fb_set_var(), and then fb_videomode_to_var() is called. If it fails to add the mode to fb_info->modelist, fb_set_var() returns error, but does not restore the old value of fb_info->var. Restore fb_info->var on failure the same way it is done earlier in the function. Found by Linux Verification Center (linuxtesting.org) with Syzkaller.
- CVSS
- Not yet scored
- Weakness (CWE)
- Not given
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- Linux
- NVD analysis
- Not yet received
- Record last updated
- Oct 15, 2026
- First seen by InfoSec Signals
- Oct 15, 2026
Affected products
Linux Linux linux:linux (from the name) | from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 before ee20216f12d9482cd70e44dae5e7fabb38367c71; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 before fab201d72fde38d081e2c5d4ad25595c535b7b22; 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 builds before 1a10d91766eb6ddfd5414e4785611e33a4fe0f9b; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 before ff0e037241173b574b385bff53d67567b9816db5; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 before 3ca78032a388a0795201792b36e6fc9b6e6e8eed; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 before b3071bb463ea1e6c686d0dc9638fc940f2f5cf17; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 before 8a3a2887794b2c8e78b3e5d6e3de724527c9f41b; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 before 05f6e183879d9785a3cdf2f08a498bc31b7a20aa | CNA record |
Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP siemens:simatic_s7_1500_cpu_1518_4_pn_dp_mfp (from the name) | from V3.1.5 | CISA ADP |
Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP siemens:simatic_s7_1500_cpu_1518f_4_pn_dp_mfp (from the name) | from V3.1.5 | CISA ADP |
Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP siemens:siplus_s7_1500_cpu_1518_4_pn_dp_mfp (from the name) | from V3.1.5 | CISA ADP |
References
- https://git.kernel.org/stable/c/ee20216f12d9482cd70e44dae5e7fabb38367c71
- https://git.kernel.org/stable/c/fab201d72fde38d081e2c5d4ad25595c535b7b22
- https://git.kernel.org/stable/c/1a10d91766eb6ddfd5414e4785611e33a4fe0f9b
- https://git.kernel.org/stable/c/ff0e037241173b574b385bff53d67567b9816db5
- https://git.kernel.org/stable/c/3ca78032a388a0795201792b36e6fc9b6e6e8eed
- https://git.kernel.org/stable/c/b3071bb463ea1e6c686d0dc9638fc940f2f5cf17
- https://git.kernel.org/stable/c/8a3a2887794b2c8e78b3e5d6e3de724527c9f41b
- https://git.kernel.org/stable/c/05f6e183879d9785a3cdf2f08a498bc31b7a20aa
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.