CVE-2023-52973 (GCVE-0-2023-52973)
Vulnerability from cvelistv5
Published
2025-03-27 16:43
Modified
2026-05-11 19:36
Severity ?
7.8 (High) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: vc_screen: move load of struct vc_data pointer in vcs_read() to avoid UAF After a call to console_unlock() in vcs_read() the vc_data struct can be freed by vc_deallocate(). Because of that, the struct vc_data pointer load must be done at the top of while loop in vcs_read() to avoid a UAF when vcs_size() is called. Syzkaller reported a UAF in vcs_size(). BUG: KASAN: use-after-free in vcs_size (drivers/tty/vt/vc_screen.c:215) Read of size 4 at addr ffff8881137479a8 by task 4a005ed81e27e65/1537 CPU: 0 PID: 1537 Comm: 4a005ed81e27e65 Not tainted 6.2.0-rc5 #1 Hardware name: Red Hat KVM, BIOS 1.15.0-2.module Call Trace: <TASK> __asan_report_load4_noabort (mm/kasan/report_generic.c:350) vcs_size (drivers/tty/vt/vc_screen.c:215) vcs_read (drivers/tty/vt/vc_screen.c:415) vfs_read (fs/read_write.c:468 fs/read_write.c:450) ... </TASK> Allocated by task 1191: ... kmalloc_trace (mm/slab_common.c:1069) vc_allocate (./include/linux/slab.h:580 ./include/linux/slab.h:720 drivers/tty/vt/vt.c:1128 drivers/tty/vt/vt.c:1108) con_install (drivers/tty/vt/vt.c:3383) tty_init_dev (drivers/tty/tty_io.c:1301 drivers/tty/tty_io.c:1413 drivers/tty/tty_io.c:1390) tty_open (drivers/tty/tty_io.c:2080 drivers/tty/tty_io.c:2126) chrdev_open (fs/char_dev.c:415) do_dentry_open (fs/open.c:883) vfs_open (fs/open.c:1014) ... Freed by task 1548: ... kfree (mm/slab_common.c:1021) vc_port_destruct (drivers/tty/vt/vt.c:1094) 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:2776) ... The buggy address belongs to the object at ffff888113747800 which belongs to the cache kmalloc-1k of size 1024 The buggy address is located 424 bytes inside of 1024-byte region [ffff888113747800, ffff888113747c00) The buggy address belongs to the physical page: page:00000000b3fe6c7c refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x113740 head:00000000b3fe6c7c order:3 compound_mapcount:0 subpages_mapcount:0 compound_pincount:0 anon flags: 0x17ffffc0010200(slab|head|node=0|zone=2|lastcpupid=0x1fffff) raw: 0017ffffc0010200 ffff888100042dc0 0000000000000000 dead000000000001 raw: 0000000000000000 0000000000100010 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff888113747880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888113747900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > ffff888113747980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888113747a00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888113747a80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== Disabling lock debugging due to kernel taint
References
Impacted products
Vendor Product Version
Linux Linux Version: ac751efa6a0d70f2c9daef5c7e3a92270f5c2dff
Version: ac751efa6a0d70f2c9daef5c7e3a92270f5c2dff
Version: ac751efa6a0d70f2c9daef5c7e3a92270f5c2dff
Version: ac751efa6a0d70f2c9daef5c7e3a92270f5c2dff
Version: ac751efa6a0d70f2c9daef5c7e3a92270f5c2dff
Version: ac751efa6a0d70f2c9daef5c7e3a92270f5c2dff
Version: ac751efa6a0d70f2c9daef5c7e3a92270f5c2dff
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              "confidentialityImpact": "HIGH",
              "integrityImpact": "HIGH",
              "privilegesRequired": "LOW",
              "scope": "UNCHANGED",
              "userInteraction": "NONE",
              "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
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                "timestamp": "2025-03-27T16:59:54.662104Z",
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          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
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      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nvc_screen: move load of struct vc_data pointer in vcs_read() to avoid UAF\n\nAfter a call to console_unlock() in vcs_read() the vc_data struct can be\nfreed by vc_deallocate(). Because of that, the struct vc_data pointer\nload must be done at the top of while loop in vcs_read() to avoid a UAF\nwhen vcs_size() is called.\n\nSyzkaller reported a UAF in vcs_size().\n\nBUG: KASAN: use-after-free in vcs_size (drivers/tty/vt/vc_screen.c:215)\nRead of size 4 at addr ffff8881137479a8 by task 4a005ed81e27e65/1537\n\nCPU: 0 PID: 1537 Comm: 4a005ed81e27e65 Not tainted 6.2.0-rc5 #1\nHardware name: Red Hat KVM, BIOS 1.15.0-2.module\nCall Trace:\n  \u003cTASK\u003e\n__asan_report_load4_noabort (mm/kasan/report_generic.c:350)\nvcs_size (drivers/tty/vt/vc_screen.c:215)\nvcs_read (drivers/tty/vt/vc_screen.c:415)\nvfs_read (fs/read_write.c:468 fs/read_write.c:450)\n...\n  \u003c/TASK\u003e\n\nAllocated by task 1191:\n...\nkmalloc_trace (mm/slab_common.c:1069)\nvc_allocate (./include/linux/slab.h:580 ./include/linux/slab.h:720\n     drivers/tty/vt/vt.c:1128 drivers/tty/vt/vt.c:1108)\ncon_install (drivers/tty/vt/vt.c:3383)\ntty_init_dev (drivers/tty/tty_io.c:1301 drivers/tty/tty_io.c:1413\n     drivers/tty/tty_io.c:1390)\ntty_open (drivers/tty/tty_io.c:2080 drivers/tty/tty_io.c:2126)\nchrdev_open (fs/char_dev.c:415)\ndo_dentry_open (fs/open.c:883)\nvfs_open (fs/open.c:1014)\n...\n\nFreed by task 1548:\n...\nkfree (mm/slab_common.c:1021)\nvc_port_destruct (drivers/tty/vt/vt.c:1094)\ntty_port_destructor (drivers/tty/tty_port.c:296)\ntty_port_put (drivers/tty/tty_port.c:312)\nvt_disallocate_all (drivers/tty/vt/vt_ioctl.c:662 (discriminator 2))\nvt_ioctl (drivers/tty/vt/vt_ioctl.c:903)\ntty_ioctl (drivers/tty/tty_io.c:2776)\n...\n\nThe buggy address belongs to the object at ffff888113747800\n  which belongs to the cache kmalloc-1k of size 1024\nThe buggy address is located 424 bytes inside of\n  1024-byte region [ffff888113747800, ffff888113747c00)\n\nThe buggy address belongs to the physical page:\npage:00000000b3fe6c7c refcount:1 mapcount:0 mapping:0000000000000000\n     index:0x0 pfn:0x113740\nhead:00000000b3fe6c7c order:3 compound_mapcount:0 subpages_mapcount:0\n     compound_pincount:0\nanon flags: 0x17ffffc0010200(slab|head|node=0|zone=2|lastcpupid=0x1fffff)\nraw: 0017ffffc0010200 ffff888100042dc0 0000000000000000 dead000000000001\nraw: 0000000000000000 0000000000100010 00000001ffffffff 0000000000000000\npage dumped because: kasan: bad access detected\n\nMemory state around the buggy address:\n  ffff888113747880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb\n  ffff888113747900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb\n\u003e ffff888113747980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb\n                                   ^\n  ffff888113747a00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb\n  ffff888113747a80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb\n==================================================================\nDisabling lock debugging due to kernel taint"
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-05-11T19:36:11.829Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/af79ea9a2443016f64d8fd8d72020cc874f0e066"
        },
        {
          "url": "https://git.kernel.org/stable/c/6332f52f44b9776568bf3c0b714ddfb0bb175e78"
        },
        {
          "url": "https://git.kernel.org/stable/c/d0332cbf53dad06a22189cc341391237f4ea6d9f"
        },
        {
          "url": "https://git.kernel.org/stable/c/55515d7d8743b71b80bfe68e89eb9d92630626ab"
        },
        {
          "url": "https://git.kernel.org/stable/c/fc9e27f3ba083534b8bbf72ab0f5c810ffdc7d18"
        },
        {
          "url": "https://git.kernel.org/stable/c/8506f16aae9daf354e3732bcfd447e2a97f023df"
        },
        {
          "url": "https://git.kernel.org/stable/c/226fae124b2dac217ea5436060d623ff3385bc34"
        }
      ],
      "title": "vc_screen: move load of struct vc_data pointer in vcs_read() to avoid UAF",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2023-52973",
    "datePublished": "2025-03-27T16:43:12.756Z",
    "dateReserved": "2025-03-27T16:40:15.737Z",
    "dateUpdated": "2026-05-11T19:36:11.829Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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