Linux: Improper Locking
CVE-2026-43215 is a high-severity improper locking 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 unauthenticated attacker, but only if a user takes part, for example by opening a link or file. The record lists versions 92d197ef7e9bb4994dae2bb17c2f19fa09d219a2, 953953abb66e52c224057ab91e404284fefeab62, 601dd3b79769b38d30b693c40afdb2a4b7edf9d0 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 0.32% 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 92d197ef7e9bb4994dae2bb17c2f19fa09d219a2 or 953953abb66e52c224057ab91e404284fefeab62 or 601dd3b79769b38d30b693c40afdb2a4b7edf9d0 or 3969db6b22e3d90d8c5f22ac1a7fe0350a94c136, whichever matches your release line, or a later version.
- Update Linux Kernel to 6.6.128 or 6.12.75 or 6.18.16 or 6.19.6, whichever matches your release line, or a later version.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
- Because the attack needs a user to take part, warn users about unexpected links and files related to this product until it is patched.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | d7d7a66aacd6fd8ca57baf08a7bac5421282f6f8 up to, but not including, 92d197ef7e9bb4994dae2bb17c2f19fa09d219a2; d7d7a66aacd6fd8ca57baf08a7bac5421282f6f8 up to, but not including, 953953abb66e52c224057ab91e404284fefeab62; d7d7a66aacd6fd8ca57baf08a7bac5421282f6f8 up to, but not including, 601dd3b79769b38d30b693c40afdb2a4b7edf9d0; d7d7a66aacd6fd8ca57baf08a7bac5421282f6f8 up to, but not including, 3969db6b22e3d90d8c5f22ac1a7fe0350a94c136; d7d7a66aacd6fd8ca57baf08a7bac5421282f6f8 up to, but not including, 8c59eeeeffa1524ef57e173a89a1a3ff539888d5; d7d7a66aacd6fd8ca57baf08a7bac5421282f6f8 up to, but not including, 96c4af418586ee9a6aab61738644366426e05316; 6.0 | 92d197ef7e9bb4994dae2bb17c2f19fa09d219a2, 953953abb66e52c224057ab91e404284fefeab62, 601dd3b79769b38d30b693c40afdb2a4b7edf9d0, 3969db6b22e3d90d8c5f22ac1a7fe0350a94c136, 8c59eeeeffa1524ef57e173a89a1a3ff539888d5, 96c4af418586ee9a6aab61738644366426e05316 |
| Linux | Linux Kernel | 6.0 up to, but not including, 6.6.128; 6.7 up to, but not including, 6.12.75; 6.13 up to, but not including, 6.18.16; 6.19 up to, but not including, 6.19.6 | 6.6.128, 6.12.75, 6.18.16, 6.19.6 |
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
- NoneNo account or login is needed.
- User interaction
- RequiredA user must take an action such as opening a file or link.
- 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:N/UI:R/S:U/C:H/I:H/A:H. Scored by CNA.
Official description
In the Linux kernel, the following vulnerability has been resolved: cifs: Fix locking usage for tcon fields We used to use the cifs_tcp_ses_lock to protect a lot of objects that are not just the server, ses or tcon lists. We later introduced srv_lock, ses_lock and tc_lock to protect fields within the corresponding structs. This was done to provide a more granular protection and avoid unnecessary serialization. There were still a couple of uses of cifs_tcp_ses_lock to provide tcon fields. In this patch, I've replaced them with tc_lock.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Locking
The product does not properly acquire or release a lock on a resource, leading to unexpected resource state changes and behaviors.
How developers prevent this class of flaw
- Use industry standard APIs to implement locking mechanism.
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/3969db6b22e3d90d8c5f22ac1a7fe0350a94c136
- git.kernel.org/stable/c/601dd3b79769b38d30b693c40afdb2a4b7edf9d0
- git.kernel.org/stable/c/8c59eeeeffa1524ef57e173a89a1a3ff539888d5
- git.kernel.org/stable/c/953953abb66e52c224057ab91e404284fefeab62
- git.kernel.org/stable/c/96c4af418586ee9a6aab61738644366426e05316
Other references
Recent Improper Locking vulnerabilities
- 7.5 High severity
- 7.8 High severity
- 7.5 High severity
- 7.8 High severity
- 8.8 High severity
- 7.5 High severity
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