CyberSecBulletin
CVE-2026-52918NVD status: Modified

Linux: Concurrent Execution using Shared Resource with Improper Synchronization

Published Updated By the CyberSecBulletin desk

CVE-2026-52918 is a high-severity concurrent execution using shared resource with improper synchronization 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 d9ce4de05df2385c19e2c7d12f529144e1a44af1, 41c8c1c7923e86e0eb59cfb4279349112756a336, 4ec17782fd186f901a7329605d11048b085b945a 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 0.22% 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 d9ce4de05df2385c19e2c7d12f529144e1a44af1 or 41c8c1c7923e86e0eb59cfb4279349112756a336 or 4ec17782fd186f901a7329605d11048b085b945a or be43e6b4043113c3b3cf887c3c8350f67140274c, whichever matches your release line, or a later version.
  2. Update Linux Kernel to 5.10.259 or 5.15.210 or 6.1.176 or 6.6.142, whichever matches your release line, or a later version.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinux1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 up to, but not including, d9ce4de05df2385c19e2c7d12f529144e1a44af1; 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 up to, but not including, 41c8c1c7923e86e0eb59cfb4279349112756a336; 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 up to, but not including, 4ec17782fd186f901a7329605d11048b085b945a; 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 up to, but not including, be43e6b4043113c3b3cf887c3c8350f67140274c; 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 up to, but not including, 85f8674cae82053f1e6bab295f6a8422cca14db5; 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 up to, but not including, 8b4c412e001b0c670eb937beab491af974da55b3; 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 up to, but not including, a218bf69eb51fefe59a3976fa8925261141f681c; 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 up to, but not including, e83f5e24da741fa9405aeeff00b08c5ee7c37b88; and 1 more rangesd9ce4de05df2385c19e2c7d12f529144e1a44af1, 41c8c1c7923e86e0eb59cfb4279349112756a336, 4ec17782fd186f901a7329605d11048b085b945a, be43e6b4043113c3b3cf887c3c8350f67140274c, 85f8674cae82053f1e6bab295f6a8422cca14db5, 8b4c412e001b0c670eb937beab491af974da55b3
SiemensSIMATIC S7-1500 TM MFP - GNU/Linux subsystemall versionsNot stated
LinuxLinux Kernel2.6.12.1 up to, but not including, 5.10.259; 5.11 up to, but not including, 5.15.210; 5.16 up to, but not including, 6.1.176; 6.2 up to, but not including, 6.6.142; 6.7 up to, but not including, 6.12.92; 6.13 up to, but not including, 6.18.34; 6.19 up to, but not including, 7.0.11; 2.6.12; and 1 more ranges5.10.259, 5.15.210, 6.1.176, 6.6.142, 6.12.92, 6.18.34

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: serialize accept_q access bt_sock_poll() walks the accept queue without synchronization, while child teardown can unlink the same socket and drop its last reference. The unsynchronized accept queue walk has existed since the initial Bluetooth import. Protect accept_q with a dedicated lock for queue updates and polling. Also rework bt_accept_dequeue() to take temporary child references under the queue lock before dropping it and locking the child socket.

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

The underlying weakness: Concurrent Execution using Shared Resource with Improper Synchronization

The product contains a concurrent code sequence that requires temporary, exclusive access to a shared resource, but a timing window exists in which the shared resource can be modified by another code sequence operating concurrently.

How developers prevent this class of flaw

  • In languages that support it, use synchronization primitives. Only wrap these around critical code to minimize the impact on performance.
  • Use thread-safe capabilities such as the data access abstraction in Spring.
  • Minimize the usage of shared resources in order to remove as much complexity as possible from the control flow and to reduce the likelihood of unexpected conditions occurring. Additionally, this will minimize the amount of synchronization necessary and may even help to reduce the likelihood of a denial of service where an attacker may be able to repeatedly trigger a critical section (CWE-400).

More Concurrent Execution using Shared Resource with Improper Synchronization vulnerabilities (CWE-362)

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 Concurrent Execution using Shared Resource with Improper Synchronization vulnerabilities

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