What is CVE-2025-38256?

CVE-2025-38256 is a Medium severity Linux kernel vulnerability with a CVSS score of 5.5 out of 10, affecting Linux kernel versions from 6.12 onward and patched in 6.12.36, 6.15.5 and 6.16. CVE-2025-38256 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

What is the CVSS score for CVE-2025-38256?

CVE-2025-38256 has a CVSS score of 5.5 out of 10, rated Medium severity. The vector string is CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H.

Is there a patch available for CVE-2025-38256?

Yes, CVE-2025-38256 has been patched. Fixed versions include 6.12.36, 6.15.5 and 6.16. If you are running Linux kernel 6.12 or later up to the fix versions, apply the relevant patch for your kernel branch.

Is CVE-2025-38256 actively exploited?

CVE-2025-38256 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

CVE-2025-38256

Medium

In the Linux kernel, the following vulnerability has been resolved: io_uring/rsrc: fix folio unpinning syzbot complains about an unmapping failure: [ 108.070381][ T14] kernel BUG at mm/gup.c:71! [ 108.070502][ T14] Internal error: Oops - BUG: 00000000f2000800 [#1] SMP [ 108.123672][ T14] Hardware name: QEMU KVM Virtual Machine, BIOS edk2-20250221-8.fc42 02/21/2025 [ 108.127458][ T14] Workqueue: iou_exit io_ring_exit_work [ 108.174205][ T14] Call trace: [ 108.175649][ T14] sanity_check_pinned_pages+0x7cc/0x7d0 (P) [ 108.178138][ T14] unpin_user_page+0x80/0x10c [ 108.180189][ T14] io_release_ubuf+0x84/0xf8 [ 108.182196][ T14] io_free_rsrc_node+0x250/0x57c [ 108.184345][ T14] io_rsrc_data_free+0x148/0x298 [ 108.186493][ T14] io_sqe_buffers_unregister+0x84/0xa0 [ 108.188991][ T14] io_ring_ctx_free+0x48/0x480 [ 108.191057][ T14] io_ring_exit_work+0x764/0x7d8 [ 108.193207][ T14] process_one_work+0x7e8/0x155c [ 108.195431][ T14] worker_thread+0x958/0xed8 [ 108.197561][ T14] kthread+0x5fc/0x75c [ 108.199362][ T14] ret_from_fork+0x10/0x20 We can pin a tail page of a folio, but then io_uring will try to unpin the head page of the folio. While it should be fine in terms of keeping the page actually alive, mm folks say it's wrong and triggers a debug warning. Use unpin_user_folio() instead of unpin_user_page*. [axboe: adapt to current tree, massage commit message]

Package Linux Kernel

Published 2025-07-09

Last modified 2025-11-19

CVSS version 3.1

Patch available

Yes

CVSS 3.1 score

5.5

out of 10

Medium

Attack Vector

Local

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Unchanged

Confidentiality

Low

Integrity

None

Availability

High

Vector string

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Affected versions

Linux kernel versions 6.12 and later are affected. Fixed in 6.12.36, 6.15.5, 6.16 and their respective stable series.

Affected from

≥ 6.12

Fixed in

✓ 6.12.36 6.12.x ✓ 6.15.5 6.15.x ✓ 6.16

References

The following references provide additional information about CVE-2025-38256 including vendor advisories, patch commits, exploit details, and third-party analysis. Links are sourced from the NIST NVD database.

Kernel patch commit
https://git.kernel.org/stable/c/11e7b7369e655e6131387b174218d7fa9557b3da
Patch
Kernel patch commit
https://git.kernel.org/stable/c/53fd75f25b223878b5fff14932e3a22f42b54f77
Patch
Kernel patch commit
https://git.kernel.org/stable/c/5afb4bf9fc62d828647647ec31745083637132e4
Patch

Details

CVE ID CVE-2025-38256

Severity Medium

CVSS score 5.5 / 10

CVSS version 3.1

Published 2025-07-09

Modified 2025-11-19

KEV No

Patch

Yes

Package linux

Frequently asked questions

What is CVE-2025-38256?

CVE-2025-38256 is a Medium severity Linux kernel vulnerability with a CVSS score of 5.5 out of 10 . It affects Linux kernel versions from 6.12 onward and has been patched in 6.12.36, 6.15.5 and 6.16. CVE-2025-38256 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
What is the CVSS score for CVE-2025-38256?

CVE-2025-38256 has a CVSS score of 5.5 out of 10, rated Medium severity (CVSS 3.1). The vector string is CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H.
Is there a patch available for CVE-2025-38256?

Yes — CVE-2025-38256 has been patched. Fixed versions include 6.12.36, 6.15.5 and 6.16. If you are running Linux kernel 6.12 or later up to the fix versions, apply the relevant patch for your kernel branch.
Is CVE-2025-38256 actively exploited?

No — CVE-2025-38256 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.