--- id: CVE-2023-53747 title: 'vc_screen: reload load of struct vc_data pointer in vcs_write() to avoid UAF' summary: |- In the Linux kernel, the following vulnerability has been resolved: vc_screen: reload load of struct vc_data pointer in vcs_write() to avoid UAF After a call to console_unlock() in vcs_write() the vc_data struct can be freed by vc_port… severity: high cvss: 7.8 cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H' cvssSource: cna vendor: Linux product: Linux affected: - >- Linux >= ac751efa6a0d70f2c9daef5c7e3a92270f5c2dff < 934de9a9b659785fed3e820bc0c813a460c71fea - >- Linux >= ac751efa6a0d70f2c9daef5c7e3a92270f5c2dff < 0deff678157333d775af190f84696336cdcccd6d - >- Linux >= ac751efa6a0d70f2c9daef5c7e3a92270f5c2dff < a4e3c4c65ae8510e01352c9a4347e05c035b2ce2 - >- Linux >= ac751efa6a0d70f2c9daef5c7e3a92270f5c2dff < 11dddfbb7a4e62489b01074d6c04d9d1b42e4047 - >- Linux >= ac751efa6a0d70f2c9daef5c7e3a92270f5c2dff < e3d1adcad5b73c7ed0c7edb35ab68abcaa45cf67 - >- Linux >= ac751efa6a0d70f2c9daef5c7e3a92270f5c2dff < 3338d0b9acde770ee588eead5cac32c25e7048fc - >- Linux >= ac751efa6a0d70f2c9daef5c7e3a92270f5c2dff < 1de42e7653d6714a7507ba6696151a1fa028c69f - >- Linux >= ac751efa6a0d70f2c9daef5c7e3a92270f5c2dff < 8fb9ea65c9d1338b0d2bb0a9122dc942cdd32357 - Linux 2.6.38 ssvc: exploitation: none automatable: 'no' technicalImpact: total timestamp: '2026-10-15T21:36:57.834897Z' published: '2025-12-08' updated: '2026-10-15' sourceUpdated: '2026-10-15T21:41:35.219Z' source: CVEORG sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2023-53747' references: - url: 'https://git.kernel.org/stable/c/934de9a9b659785fed3e820bc0c813a460c71fea' - url: 'https://git.kernel.org/stable/c/0deff678157333d775af190f84696336cdcccd6d' - url: 'https://git.kernel.org/stable/c/a4e3c4c65ae8510e01352c9a4347e05c035b2ce2' - url: 'https://git.kernel.org/stable/c/11dddfbb7a4e62489b01074d6c04d9d1b42e4047' - url: 'https://git.kernel.org/stable/c/e3d1adcad5b73c7ed0c7edb35ab68abcaa45cf67' - url: 'https://git.kernel.org/stable/c/3338d0b9acde770ee588eead5cac32c25e7048fc' - url: 'https://git.kernel.org/stable/c/1de42e7653d6714a7507ba6696151a1fa028c69f' - url: 'https://git.kernel.org/stable/c/8fb9ea65c9d1338b0d2bb0a9122dc942cdd32357' tags: - cve.org epss: 0.00139 epssPercentile: 0.02892 ingestedAt: '2026-10-15T22:48:25.418Z' --- ## Overview In the Linux kernel, the following vulnerability has been resolved: vc_screen: reload load of struct vc_data pointer in vcs_write() to avoid UAF After a call to console_unlock() in vcs_write() the vc_data struct can be freed by vc_port_destruct(). Because of that, the struct vc_data pointer must be reloaded in the while loop in vcs_write() after console_lock() to avoid a UAF when vcs_size() is called. Syzkaller reported a UAF in vcs_size(). BUG: KASAN: slab-use-after-free in vcs_size (drivers/tty/vt/vc_screen.c:215) Read of size 4 at addr ffff8880beab89a8 by task repro_vcs_size/4119 Call Trace: __asan_report_load4_noabort (mm/kasan/report_generic.c:380) vcs_size (drivers/tty/vt/vc_screen.c:215) vcs_write (drivers/tty/vt/vc_screen.c:664) vfs_write (fs/read_write.c:582 fs/read_write.c:564) ... Allocated by task 1213: kmalloc_trace (mm/slab_common.c:1064) vc_allocate (./include/linux/slab.h:559 ./include/linux/slab.h:680 drivers/tty/vt/vt.c:1078 drivers/tty/vt/vt.c:1058) con_install (drivers/tty/vt/vt.c:3334) tty_init_dev (drivers/tty/tty_io.c:1303 drivers/tty/tty_io.c:1415 drivers/tty/tty_io.c:1392) tty_open (drivers/tty/tty_io.c:2082 drivers/tty/tty_io.c:2128) chrdev_open (fs/char_dev.c:415) do_dentry_open (fs/open.c:921) vfs_open (fs/open.c:1052) ... Freed by task 4116: kfree (mm/slab_common.c:1016) vc_port_destruct (drivers/tty/vt/vt.c:1044) tty_port_destructor (drivers/tty/tty_port.c:296) tty_port_put (drivers/tty/tty_port.c:312) vt_disallocate_all (drivers/tty/vt/vt_ioctl.c:662 (discriminator 2)) vt_ioctl (drivers/tty/vt/vt_ioctl.c:903) tty_ioctl (drivers/tty/tty_io.c:2778) ... The buggy address belongs to the object at ffff8880beab8800 which belongs to the cache kmalloc-1k of size 1024 The buggy address is located 424 bytes inside of freed 1024-byte region [ffff8880beab8800, ffff8880beab8c00) The buggy address belongs to the physical page: page:00000000afc77580 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0xbeab8 head:00000000afc77580 order:3 entire_mapcount:0 nr_pages_mapped:0 pincount:0 flags: 0xfffffc0010200(slab|head|node=0|zone=1|lastcpupid=0x1fffff) page_type: 0xffffffff() raw: 000fffffc0010200 ffff888100042dc0 ffffea000426de00 dead000000000002 raw: 0000000000000000 0000000000100010 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8880beab8880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880beab8900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff8880beab8980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8880beab8a00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880beab8a80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== Disabling lock debugging due to kernel taint ## Affected - `Linux >= ac751efa6a0d70f2c9daef5c7e3a92270f5c2dff < 934de9a9b659785fed3e820bc0c813a460c71fea` - `Linux >= ac751efa6a0d70f2c9daef5c7e3a92270f5c2dff < 0deff678157333d775af190f84696336cdcccd6d` - `Linux >= ac751efa6a0d70f2c9daef5c7e3a92270f5c2dff < a4e3c4c65ae8510e01352c9a4347e05c035b2ce2` - `Linux >= ac751efa6a0d70f2c9daef5c7e3a92270f5c2dff < 11dddfbb7a4e62489b01074d6c04d9d1b42e4047` - `Linux >= ac751efa6a0d70f2c9daef5c7e3a92270f5c2dff < e3d1adcad5b73c7ed0c7edb35ab68abcaa45cf67` - `Linux >= ac751efa6a0d70f2c9daef5c7e3a92270f5c2dff < 3338d0b9acde770ee588eead5cac32c25e7048fc` - `Linux >= ac751efa6a0d70f2c9daef5c7e3a92270f5c2dff < 1de42e7653d6714a7507ba6696151a1fa028c69f` - `Linux >= ac751efa6a0d70f2c9daef5c7e3a92270f5c2dff < 8fb9ea65c9d1338b0d2bb0a9122dc942cdd32357` - `Linux 2.6.38` ## Remediation Refer to the linked advisories for vendor-supplied fixes and affected version ranges.