CyberSecBulletin
CVE-2026-63974NVD status: Analyzed

Linux: Uncontrolled Resource Consumption

Published Updated By the CyberSecBulletin desk

CVE-2026-63974 is a high-severity uncontrolled resource consumption vulnerability in Linux, with a CVSS 3.1 base score of 8.8 out of 10. It can be exploited from the same local network by an unauthenticated attacker, without any action from a user. The record lists versions ccf07dfb9d7d1e2c7a1eeb782f90d9b614ebba9c, 7b81c1378b79c3143ca3fdb3d18ac0f01cbabb21, 9cebe4680bb9a72f80c6541eb24af06db7a1fbc9 as the first without the flaw, so updating Linux to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.35% chance of exploitation within 30 days, which is low compared with other CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Update Linux to ccf07dfb9d7d1e2c7a1eeb782f90d9b614ebba9c or 7b81c1378b79c3143ca3fdb3d18ac0f01cbabb21 or 9cebe4680bb9a72f80c6541eb24af06db7a1fbc9 or 47330cc875b36a1cf7b3543cb2cf90a7c603ce0e, whichever matches your release line, or a later version.
  2. Update Linux Kernel to 5.19 or 6.1.191 or 6.6.160 or 6.12.93, whichever matches your release line, or a later version.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinux877afadad2dce8aae1f2aad8ce47e072d4f6165e up to, but not including, ccf07dfb9d7d1e2c7a1eeb782f90d9b614ebba9c; 877afadad2dce8aae1f2aad8ce47e072d4f6165e up to, but not including, 7b81c1378b79c3143ca3fdb3d18ac0f01cbabb21; 877afadad2dce8aae1f2aad8ce47e072d4f6165e up to, but not including, 9cebe4680bb9a72f80c6541eb24af06db7a1fbc9; 877afadad2dce8aae1f2aad8ce47e072d4f6165e up to, but not including, 47330cc875b36a1cf7b3543cb2cf90a7c603ce0e; 877afadad2dce8aae1f2aad8ce47e072d4f6165e up to, but not including, 60bceb9a4c693e68cc90ba4b2dfb9e000e8638ff; 877afadad2dce8aae1f2aad8ce47e072d4f6165e up to, but not including, 525daaea459fc215f432de1b8debbd9144bf97b0; 4bf367fa1fefabdf14938d0ac9ed60020389112e; 3b382555706558f5c0587862b6dc03e96a252bba; and 3 more rangesccf07dfb9d7d1e2c7a1eeb782f90d9b614ebba9c, 7b81c1378b79c3143ca3fdb3d18ac0f01cbabb21, 9cebe4680bb9a72f80c6541eb24af06db7a1fbc9, 47330cc875b36a1cf7b3543cb2cf90a7c603ce0e, 60bceb9a4c693e68cc90ba4b2dfb9e000e8638ff, 525daaea459fc215f432de1b8debbd9144bf97b0
LinuxLinux Kernel5.18.18 up to, but not including, 5.19; 5.19.2 up to, but not including, 6.1.191; 6.2 up to, but not including, 6.6.160; 6.7 up to, but not including, 6.12.93; 6.13 up to, but not including, 6.18.35; 6.19 up to, but not including, 7.0.12; 7.15.19, 6.1.191, 6.6.160, 6.12.93, 6.18.35, 7.0.12

Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
AdjacentThe attacker must be on the same local network segment.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
NoneNo account or login is needed.
User interaction
NoneNo action by a victim is required.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
HighAll data handled by the component can be read.
Integrity
HighData or code can be modified at will.
Availability
HighThe component can be taken down completely.

Vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. Scored by CNA.

Official description

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: hci_sync: Set HCI_CMD_DRAIN_WORKQUEUE during device close Since hci_dev_close_sync() can now be called during the reset path, we should also set HCI_CMD_DRAIN_WORKQUEUE. This avoids queuing timeouts while the hdev workqueue is being drained.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Uncontrolled Resource Consumption

The product does not properly control the allocation and maintenance of a limited resource.

How developers prevent this class of flaw

  • Ensure that protocols have specific limits of scale placed on them.
  • Ensure that all failures in resource allocation place the system into a safe posture.

More Uncontrolled Resource Consumption vulnerabilities (CWE-400)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
  3. Record last changed materially (score, affected products, status or references).

References

Recent Uncontrolled Resource Consumption vulnerabilities

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