Linux: Improper Locking
CVE-2026-64232 is a critical-severity improper locking vulnerability in Linux, with a CVSS 3.1 base score of 9.8 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. The record lists versions 53a01bcc0242590eda4c452a5bd996f62457113b, 0943f81e1b3176f27dbaf6db268fc69d8a94f0ba, 42929c98d044f126508baf54a65b0f87f932fa75 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 0.43% chance of exploitation within 30 days, which is low compared with other CVEs.
Critical severity: a successful attack would have severe impact.
What to do
- Update Linux to 53a01bcc0242590eda4c452a5bd996f62457113b or 0943f81e1b3176f27dbaf6db268fc69d8a94f0ba or 42929c98d044f126508baf54a65b0f87f932fa75 or 2c6e6a18a37b905cb584eb0dda3ae482162a81ca, whichever matches your release line, or a later version.
- Update Linux Kernel to 6.12.92 or 6.18.34 or 7.0.11, 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.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | 76c313f658d2752e8527610677164aa7094ef7a5 up to, but not including, 53a01bcc0242590eda4c452a5bd996f62457113b; 76c313f658d2752e8527610677164aa7094ef7a5 up to, but not including, 0943f81e1b3176f27dbaf6db268fc69d8a94f0ba; 76c313f658d2752e8527610677164aa7094ef7a5 up to, but not including, 42929c98d044f126508baf54a65b0f87f932fa75; 76c313f658d2752e8527610677164aa7094ef7a5 up to, but not including, 2c6e6a18a37b905cb584eb0dda3ae482162a81ca; 6.12 | 53a01bcc0242590eda4c452a5bd996f62457113b, 0943f81e1b3176f27dbaf6db268fc69d8a94f0ba, 42929c98d044f126508baf54a65b0f87f932fa75, 2c6e6a18a37b905cb584eb0dda3ae482162a81ca |
| Linux | Linux Kernel | 6.12 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; 7.1 | 6.12.92, 6.18.34, 7.0.11 |
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
- 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: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: block: recompute nr_integrity_segments in blk_insert_cloned_request blk_insert_cloned_request() already recomputes nr_phys_segments against the bottom queue, because "the queue settings related to segment counting may differ from the original queue." The exact same reasoning applies to integrity segments: a stacked driver's underlying queue can have tighter virt_boundary_mask, seg_boundary_mask, or max_segment_size than the top queue, in which case blk_rq_count_integrity_sg() against the bottom queue produces a different count than the cached rq->nr_integrity_segments inherited from the source request by blk_rq_prep_clone(). When the cached count is lower than the bottom queue's actual count, blk_rq_map_integrity_sg() trips BUG_ON(segments > rq->nr_integrity_segments); on dispatch. The same families of stacked setups that motivated the existing nr_phys_segments recompute -- dm-multipath fanning out to nvme-rdma in particular -- can produce this. Mirror the nr_phys_segments handling: when the request carries integrity, recompute nr_integrity_segments against the bottom queue and reject the request if it exceeds the bottom queue's max_integrity_segments. blk_rq_count_integrity_sg() and queue_max_integrity_segments() are both already available via <linux/blk-integrity.h>, which blk-mq.c includes. This closes a latent gap in the stacking contract and brings the integrity-segment accounting in line with the existing phys-segment accounting.
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: yes, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
Recent Improper Locking vulnerabilities
- 7.8 High severity
- 9.8 Critical severity
- 9.8 Critical severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
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