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CVE-2026-53385

Full vulnerability record from the local CVENow database.

Description

In the Linux kernel, the following vulnerability has been resolved: vc_screen: fix null-ptr-deref in vcs_notifier() during concurrent vcs_write A KASAN null-ptr-deref was observed in vcs_notifier(): BUG: KASAN: null-ptr-deref in vcs_notifier+0x98/0x130 Read of size 2 at addr qmp_cmd_name: qmp_capabilities, arguments: {} The issue is a race condition in vcs_write(). When the console_lock is temporarily dropped (to copy data from userspace), the vc_data pointer obtained from vcs_vc() may become stale. After re-acquiring the lock, vcs_vc() is called again to re-validate the pointer. If the vc has been deallocated in the meantime, vcs_vc() returns NULL, and the while loop breaks (with written > 0). However, after the loop, vcs_scr_updated(vc) is still called with the now-NULL vc pointer, leading to a null pointer dereference in the notifier chain (vcs_notifier dereferences param->vc). Fix this by adding a NULL check for vc before calling vcs_scr_updated().

Severity
MEDIUM
CVSS score
5.5 (v3.1)
Vulnerability status
Analyzed
Source identifier
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Published
2026-07-19 12:16:49.387000
Last modified
2026-11-06 17:18:28.240000
View original CVE JSON
{
  "id": "CVE-2026-53385",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "published": "2026-07-19T12:16:49.387",
  "lastModified": "2026-11-06T17:18:28.240",
  "vulnStatus": "Analyzed",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nvc_screen: fix null-ptr-deref in vcs_notifier() during concurrent vcs_write\n\nA KASAN null-ptr-deref was observed in vcs_notifier():\n\nBUG: KASAN: null-ptr-deref in vcs_notifier+0x98/0x130\nRead of size 2 at addr qmp_cmd_name: qmp_capabilities, arguments: {}\n\nThe issue is a race condition in vcs_write(). When the console_lock is\ntemporarily dropped (to copy data from userspace), the vc_data pointer\nobtained from vcs_vc() may become stale. After re-acquiring the lock,\nvcs_vc() is called again to re-validate the pointer. If the vc has been\ndeallocated in the meantime, vcs_vc() returns NULL, and the while loop\nbreaks (with written > 0). However, after the loop, vcs_scr_updated(vc)\nis still called with the now-NULL vc pointer, leading to a null pointer\ndereference in the notifier chain (vcs_notifier dereferences param->vc).\n\nFix this by adding a NULL check for vc before calling vcs_scr_updated()."
    }
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          "scope": "UNCHANGED",
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      "source": "[email protected]",
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      "description": [
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