CVE-2026-64232: Linux kernel · block: recompute nr_integrity_segments in blk_insert_cloned_request
Affects Linux kernelSource CVE Database V5
Not known to be exploited · CVSS 9.8 Critical · fixed in 42929c98d044f126508baf54a65b0f87f932fa75 : patch Linux kernel as a priority.
Data as of 26 Oct 2026, 14:05 UTC
- EPSS
- 0.4% chance of exploitation in 30 days – higher than 37% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- CISA SSVC
- Exploitation
- No evidence of active exploitation and no public proof of concept
- Automatable
- Attackers can reliably automate steps 1–4 of the kill chain
- Technical impact
- Total control over the software or total information disclosure
CISA SSVC assessment, 2026-10-16.
- Patch
- Available – fixed in 42929c98d044f126508baf54a65b0f87f932fa75, 0943f81e1b3176f27dbaf6db268fc69d8a94f0ba, 53a01bcc0242590eda4c452a5bd996f62457113b +1
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 24 Jul 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Upgrade Linux kernel to 42929c98d044f126508baf54a65b0f87f932fa75, 0943f81e1b3176f27dbaf6db268fc69d8a94f0ba, 53a01bcc0242590eda4c452a5bd996f62457113b or 2c6e6a18a37b905cb584eb0dda3ae482162a81ca.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in– |
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.
References
- git.kernel.org/stable/c/53a01bcc0242590eda4c452a5bd996f62457113b (opens in a new tab)
- git.kernel.org/stable/c/0943f81e1b3176f27dbaf6db268fc69d8a94f0ba (opens in a new tab)
- git.kernel.org/stable/c/42929c98d044f126508baf54a65b0f87f932fa75 (opens in a new tab)
- git.kernel.org/stable/c/2c6e6a18a37b905cb584eb0dda3ae482162a81ca (opens in a new tab)