CVE-2025-40291

High

In the Linux kernel, the following vulnerability has been resolved: io_uring: fix regbuf vector size truncation There is a report of io_estimate_bvec_size() truncating the calculated number of segments that leads to corruption issues. Check it doesn't overflow "int"s used later. Rough but simple, can be improved on top.

Package Linux Kernel
Published 2025-12-08
Last modified 2026-07-30
CVSS version 3.1
Patch available
Yes

CVSS 3.1 score

7.8

out of 10
High
Attack Vector
Local
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High
Vector string
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Affected versions

Linux kernel versions 6.15 and later are affected. Fixed in 6.17.8, 6.18 and their respective stable series.

Affected from
≥ 6.15
Fixed in
✓ 6.17.8 6.17.x ✓ 6.18

References

2 total

Frequently asked questions

  • What is CVE-2025-40291?

    CVE-2025-40291 is a High severity Linux kernel vulnerability with a CVSS score of 7.8 out of 10 . It affects Linux kernel versions from 6.15 onward and has been patched in 6.17.8 and 6.18. CVE-2025-40291 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

  • What is the CVSS score for CVE-2025-40291?

    CVE-2025-40291 has a CVSS score of 7.8 out of 10, rated High severity (CVSS 3.1). The vector string is CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H .

  • Is there a patch available for CVE-2025-40291?

    Yes. CVE-2025-40291 has been patched. Fixed versions include 6.17.8 and 6.18. If you are running Linux kernel 6.15 or later up to the fix versions, apply the relevant patch for your kernel branch.

  • Is CVE-2025-40291 actively exploited?

    No. CVE-2025-40291 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.

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