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VulnerabilityPublished Updated

CVE-2026-64232: Linux kernel · block: recompute nr_integrity_segments in blk_insert_cloned_request

Affects Linux kernelSource CVE Database V5

0

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

CVSS 3.1 base score
9.8Critical
How severe the flaw is on the 0–10 CVSS scale.
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:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 24 Jul 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq 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

ProductAffectedFixed in
LinuxLinuxAffected
  • ≥ 76c313f658d2752e8527610677164aa7094ef7a5, < 42929c98d044f126508baf54a65b0f87f932fa75
Fixed in
  • 42929c98d044f126508baf54a65b0f87f932fa75
LinuxLinuxAffected
  • ≥ 76c313f658d2752e8527610677164aa7094ef7a5, < 0943f81e1b3176f27dbaf6db268fc69d8a94f0ba
Fixed in
  • 0943f81e1b3176f27dbaf6db268fc69d8a94f0ba
LinuxLinuxAffected
  • ≥ 76c313f658d2752e8527610677164aa7094ef7a5, < 53a01bcc0242590eda4c452a5bd996f62457113b
Fixed in
  • 53a01bcc0242590eda4c452a5bd996f62457113b
LinuxLinuxAffected
  • ≥ 76c313f658d2752e8527610677164aa7094ef7a5, < 2c6e6a18a37b905cb584eb0dda3ae482162a81ca
Fixed in
  • 2c6e6a18a37b905cb584eb0dda3ae482162a81ca
LinuxLinuxAffected
  • =6.12
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

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