Linux: Concurrent Execution using Shared Resource with Improper Synchronization
CVE-2026-53400 is a high-severity concurrent execution using shared resource with improper synchronization vulnerability in Linux, with a CVSS 3.1 base score of 7.8 out of 10. It can be exploited with local access to the system by an attacker with a low-privileged account, without any action from a user. The record lists versions 2e57c788e71f1763445f812eba4e0b4a2fbd0646, a4365bc41baaf67f3a5aa8556d23544e6ec7480a, 1febb174815bcae56d73587e99e8f87e02f0784d 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 0.14% 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 2e57c788e71f1763445f812eba4e0b4a2fbd0646 or a4365bc41baaf67f3a5aa8556d23544e6ec7480a or 1febb174815bcae56d73587e99e8f87e02f0784d or da9d8d9711f78deebc202d0cffcf577e45ee8621, whichever matches your release line, or a later version.
- Update Linux Kernel to 5.10.261 or 5.15.212 or 6.1.178 or 6.6.145, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | 6e13e641841833cc2aa5baefe89bb04bc388801b up to, but not including, 2e57c788e71f1763445f812eba4e0b4a2fbd0646; 6e13e641841833cc2aa5baefe89bb04bc388801b up to, but not including, a4365bc41baaf67f3a5aa8556d23544e6ec7480a; 6e13e641841833cc2aa5baefe89bb04bc388801b up to, but not including, 1febb174815bcae56d73587e99e8f87e02f0784d; 6e13e641841833cc2aa5baefe89bb04bc388801b up to, but not including, da9d8d9711f78deebc202d0cffcf577e45ee8621; 6e13e641841833cc2aa5baefe89bb04bc388801b up to, but not including, 78793c75dc6d0ff2e4d50ad617349b328a99054e; 6e13e641841833cc2aa5baefe89bb04bc388801b up to, but not including, 6a946038f2a5a8c29048c6af369d4e391448a5c5; 6e13e641841833cc2aa5baefe89bb04bc388801b up to, but not including, a4c8094bbf4c6fa68b17e3b16f6a0a1b7a14f3e0; 6e13e641841833cc2aa5baefe89bb04bc388801b up to, but not including, ba14d7cf2fe7284610a29854bdff22b2537d3ce6; and 1 more ranges | 2e57c788e71f1763445f812eba4e0b4a2fbd0646, a4365bc41baaf67f3a5aa8556d23544e6ec7480a, 1febb174815bcae56d73587e99e8f87e02f0784d, da9d8d9711f78deebc202d0cffcf577e45ee8621, 78793c75dc6d0ff2e4d50ad617349b328a99054e, 6a946038f2a5a8c29048c6af369d4e391448a5c5 |
| Siemens | SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AB0) | V3.1.6 and later; V3.1.7 and later | Not stated |
| Siemens | SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AC0) | V3.1.6 and later; V3.1.7 and later | Not stated |
| Siemens | SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AB0) | V3.1.6 and later; V3.1.7 and later | Not stated |
| Siemens | SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AC0) | V3.1.6 and later; V3.1.7 and later | Not stated |
| Siemens | SIPLUS S7-1500 CPU 1518-4 PN/DP MFP (6AG1518-4AX00-4AC0) | V3.1.6 and later; V3.1.7 and later | Not stated |
| Linux | Linux Kernel | 2.6.22 up to, but not including, 5.10.261; 5.11 up to, but not including, 5.15.212; 5.16 up to, but not including, 6.1.178; 6.2 up to, but not including, 6.6.145; 6.7 up to, but not including, 6.12.95; 6.13 up to, but not including, 6.18.38; 6.19 up to, but not including, 7.1.3 | 5.10.261, 5.15.212, 6.1.178, 6.6.145, 6.12.95, 6.18.38 |
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
- LocalThe attacker needs local access or must trick a user into running something.
- 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:L/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: i2c: core: fix adapter registration race Adapters can be looked up based on their id using i2c_get_adapter() which takes a reference to the embedded struct device. Make sure that the adapter (including its struct device) has been initialised before adding it to the IDR to avoid accessing uninitialised data which could, for example, lead to NULL-pointer dereferences or use-after-free. Note that the i2c-dev chardev, which is registered from a bus notifier, currently uses i2c_get_adapter() so the adapter needs to be added to the IDR before registration.
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.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
- git.kernel.org/stable/c/1febb174815bcae56d73587e99e8f87e02f0784d
- git.kernel.org/stable/c/2e57c788e71f1763445f812eba4e0b4a2fbd0646
- git.kernel.org/stable/c/6a946038f2a5a8c29048c6af369d4e391448a5c5
- git.kernel.org/stable/c/78793c75dc6d0ff2e4d50ad617349b328a99054e
- git.kernel.org/stable/c/a4365bc41baaf67f3a5aa8556d23544e6ec7480a
- git.kernel.org/stable/c/a4c8094bbf4c6fa68b17e3b16f6a0a1b7a14f3e0
- git.kernel.org/stable/c/ba14d7cf2fe7284610a29854bdff22b2537d3ce6
- git.kernel.org/stable/c/da9d8d9711f78deebc202d0cffcf577e45ee8621
Other references
Recent Concurrent Execution using Shared Resource with Improper Synchronization vulnerabilities
- 9.8 Critical severity
- 9.8 Critical severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
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