Linux: Concurrent Execution using Shared Resource with Improper Synchronization
CVE-2026-98115 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 remotely over the network by an attacker with a low-privileged account, without any action from a user. The record lists versions a7e6df0bb92642bee4431b2b85c69ada1e463b21, d12168084c8c1b6d883c8eca5853929ac5136a9e, 6.7 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 0.27% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Linux to a7e6df0bb92642bee4431b2b85c69ada1e463b21 or d12168084c8c1b6d883c8eca5853929ac5136a9e or 6.7 or 6.11, whichever matches your release line, or a later version.
- Update Linux Kernel to 6.7 or 6.11 or 7.2.7, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | 76e98a158b207771a6c9a0de0a60522a446a3447 up to, but not including, a7e6df0bb92642bee4431b2b85c69ada1e463b21; 76e98a158b207771a6c9a0de0a60522a446a3447 up to, but not including, d12168084c8c1b6d883c8eca5853929ac5136a9e; 118fd997612d1efc94a86c307c6c6d659ebe29fc; c1e55020534c4aafbc38d8f5c4583ff30755ac18; 6.6.48 up to, but not including, 6.7; 6.10.7 up to, but not including, 6.11; 6.11 | a7e6df0bb92642bee4431b2b85c69ada1e463b21, d12168084c8c1b6d883c8eca5853929ac5136a9e, 6.7, 6.11 |
| Linux | Linux Kernel | 6.6.48 up to, but not including, 6.7; 6.10.7 up to, but not including, 6.11; 6.11.1 up to, but not including, 7.2.7; 6.11; 7.3 | 6.7, 6.11, 7.2.7 |
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
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- LowA basic user account is enough.
- 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:N/AC:L/PR:L/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: ksmbd: safely drain sessions during logoff SMB3 multichannel allows requests for one session to run on multiple connections. Wait for all channels bound to a session before freeing shared session objects. A deferred byte-range lock remains counted as a running request and only wakes when its file closes. Wake blocked locks during the drain without unpublishing or modifying their file objects. Synchronous CANCEL requests must invoke their cancellation callback to wake pending operations, while CHANGE_NOTIFY completion remains specific to the asynchronous path. Serialize session teardown with channel registration and previous-session cleanup, and use atomic work-state transitions so LOGOFF, CANCEL, and connection teardown invoke cancellation callbacks only once.
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).
Timeline
- CVE record published.
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
Recent Concurrent Execution using Shared Resource with Improper Synchronization vulnerabilities
- 8.1 High severity
- 7.1 High severity
- 7.8 High severity
- 7.5 High severity
- 8.1 High severity
- 7.1 High severity
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