5.5

CVE-2025-38256: io_uring/rsrc: fix folio unpinning

Analyzed
AliasesUBUNTU-CVE-2025-38256DEBIAN-CVE-2025-38256
Published 09-07-2025Last modified 11-05-2026

Vulnerability summary

CVE-2025-38256 is a medium (CVSS 5.5) vulnerability in linux. EPSS estimates a 0.17% chance of exploitation in the next 30 days, higher than 5.7% of scored vulnerabilities.

Priority
Routine

Not severe (CVSS 5.5, local access); no exploitation reported by the 5 checked sources

Source freshness unavailable

How is this decided?
CVSS score
5.5/10
010
Medium · v3.1 (NVD)
EPSS score
0.17%
0%100%
Low · +0.01 pp in 30 days
KEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 14 · Related 14
OPENSUSE-SU-2025:20081-1SUSE-SU-2025:02853-1SUSE-SU-2025:02997-1SUSE-SU-2025:03011-1SUSE-SU-2025:21074-1SUSE-SU-2025:21139-1

Timeline

  1. 09-07-2025
    PublishedVulnerability first disclosed.
  2. 11-05-2026
    Last modifiedVulnerability information updated.

Description

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]

CVSS metrics

4 scores · 3 sources · 2 versions

EPSS trend

Probability

0.17%

Chance of exploitation in the next 30 days

Percentile

6%

Versus all other CVEs

30-day change

Increase +0.01 pp

From 0.15% on 04-10-2026

04-10-202603-11-2026

Known exploited

Compare KEV catalogs
CISA KEV

Not in the CISA KEV catalog.

ENISA CNW

Not in the ENISA CNW catalog.

CIRCL

Not in the CIRCL catalog.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

No weakness data has been published for this record.

Affected systems

Version check

Known conditions: local access, low-privilege account, no user interaction (CVSS vector). Other conditions: not stated in public data.

Ubuntu89 products
  • linux-allwinner-5.19All versions (No fix recorded)
  • linux-aws-5.0All versions (No fix recorded)
  • linux-aws-5.11All versions (No fix recorded)
  • linux-aws-5.13All versions (No fix recorded)
  • linux-aws-5.19All versions (No fix recorded)
Linux2 products
  • linux≥ a8edbb424b1391b077407c75d8f5d2ede77aa70d, < 53fd75f25b223878b5fff14932e3a22f42b54f77 | ≥ a8edbb424b1391b077407c75d8f5d2ede77aa70d, < 11e7b7369e655e6131387b174218d7fa9557b3da | ≥ a8edbb424b1391b077407c75d8f5d2ede77aa70d, < 5afb4bf9fc62d828647647ec31745083637132e4 | 6.12
  • linux_kernel≥ 6.12, < 6.12.36 | ≥ 6.13, < 6.15.5 | 6.16:rc1 | 6.16:rc2 | 6.16:rc3
Debian1 product
  • linux< 6.12.37-1

3 vendors · 92 products

References

13 links
Show all 13 references