CVE-2025-39966

HIGHNVD 7.07.0—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 7.0 under NVD CVSS v3. EPSS exploit probability: 0.1%, top 99% of all CVEs by exploit prediction. GitHub Security Advisory enrichment pending alignment with NVD CVSS.

Triggered by: NVD CVSS baseline
Sources: epss, ghsa, nvd
Trending — 3 sources updated this week
7.0
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 0%CVSS: 7.0Exploit: NoneExposed: 0

A fix is available — apply it.

In the Linux kernel, the following vulnerability has been resolved:

iommufd: Fix race during abort for file descriptors

fput() doesn't actually call file_operations release() synchronously, it puts the file on a work queue and it will be released eventually.

This is normally fine, except for iommufd the file and the iommufd_object are tied to gether. The file has the object as it's private_data and holds a users refcount, while the object is expected to remain alive as long as the file is.

When the allocation of a new object aborts before installing the file it will fput() the file and then go on to immediately kfree() the obj. This causes a UAF once the workqueue completes the fput() and tries to decrement the users refcount.

Fix this by putting the core code in charge of the file lifetime, and call __fput_sync() during abort to ensure that release() is called before kfree. __fput_sync() is a bit too tricky to open code in all the object implementations. Instead the objects tell the core code where the file pointer is and the core will take care of the life cycle.

If the object is successfully allocated then the file will hold a users refcount and the iommufd_object cannot be destroyed.

It is worth noting that close(); ioctl(IOMMU_DESTROY); doesn't have an issue because close() is already using a synchronous version of fput().

The UAF looks like this:

BUG: KASAN: slab-use-after-free in iommufd_eventq_fops_release+0x45/0xc0 drivers/iommu/iommufd/eventq.c:376 Write of size 4 at addr ffff888059c97804 by task syz.0.46/6164

CPU: 0 UID: 0 PID: 6164 Comm: syz.0.46 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0xcd/0x630 mm/kasan/report.c:482 kasan_report+0xe0/0x110 mm/kasan/report.c:595 check_region_inline mm/kasan/generic.c:183 [inline] kasan_check_range+0x100/0x1b0 mm/kasan/generic.c:189 instrument_atomic_read_write include/linux/instrumented.h:96 [inline] atomic_fetch_sub_release include/linux/atomic/atomic-instrumented.h:400 [inline] __refcount_dec include/linux/refcount.h:455 [inline] refcount_dec include/linux/refcount.h:476 [inline] iommufd_eventq_fops_release+0x45/0xc0 drivers/iommu/iommufd/eventq.c:376 __fput+0x402/0xb70 fs/file_table.c:468 task_work_run+0x14d/0x240 kernel/task_work.c:227 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline] exit_to_user_mode_loop+0xeb/0x110 kernel/entry/common.c:43 exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline] syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline] do_syscall_64+0x41c/0x4c0 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f

CVSS v3
7.0
EG Score
7.0(medium)
EG Risk
36(Track)
EG Risk 36/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity70% × 45%
Exploitation0% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS
1.1%
KEV
Not listed

Published

October 15, 2025

Last Modified

February 26, 2026

References (3)

Patch Availability(5)

Vendor / EcosystemFixed in / PatchReleasedSource
redhatkernel-0:6.12.0-124.27.1.el10_12026-01-12redhat
redhatkernel-0:5.14.0-611.16.1.el9_72025-12-17redhat
redhatkernel-0:6.12.0-55.50.1.el10_02025-12-17redhat
redhatkernel-0:5.14.0-570.72.1.el9_62025-12-09redhat
linuxKernel @ 6.12.50—osv

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

All Vendor Advisories

(4)

Every vendor that published an advisory referencing this CVE — pulled from our cve_vendor_advisories aggregation. Click any row for the vendor's original advisory page.

Data Freshness Timeline

(refreshed 11× in last 7d / 40× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-07-24 14:17 UTCEPSS rescore
  2. 2026-07-23 17:11 UTCOSV refresh
  3. 2026-07-23 02:55 UTCEG score recompute▲ 2.30
  4. 2026-07-22 14:07 UTCEPSS rescore
  5. 2026-07-22 14:07 UTCEPSS rescore
  6. 2026-07-21 15:24 UTCEPSS rescore
  7. 2026-07-20 17:07 UTCEPSS rescore
  8. 2026-07-19 02:28 UTCEPSS rescore
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  10. 2026-07-18 10:04 UTCEPSS rescore
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  12. 2026-07-16 17:02 UTCEPSS rescore
  13. 2026-07-15 16:57 UTCEPSS rescore
  14. 2026-07-15 16:57 UTCEPSS rescore
  15. 2026-07-15 01:59 UTCEPSS rescore
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  17. 2026-07-13 22:29 UTCEPSS rescore
  18. 2026-07-13 22:29 UTCEPSS rescore
  19. 2026-07-12 05:46 UTCEPSS rescore
  20. 2026-07-09 19:09 UTCEPSS rescore
  21. 2026-07-09 19:09 UTCEPSS rescore
  22. 2026-07-06 16:27 UTCEPSS rescore
  23. 2026-07-06 16:27 UTCEPSS rescore
  24. 2026-07-06 11:41 UTCOSV refresh
  25. 2026-07-06 02:23 UTCEPSS rescore
Show 50 more
  1. 2026-07-04 06:30 UTCEPSS rescore
  2. 2026-07-01 15:06 UTCEPSS rescore
  3. 2026-07-01 15:06 UTCEPSS rescore
  4. 2026-06-30 23:22 UTCEPSS rescore
  5. 2026-06-30 23:22 UTCEPSS rescore
  6. 2026-06-29 14:06 UTCEPSS rescore
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  8. 2026-06-28 14:07 UTCEPSS rescore
  9. 2026-06-28 14:07 UTCEPSS rescore
  10. 2026-06-28 04:55 UTCEPSS rescore
  11. 2026-06-28 04:55 UTCEPSS rescore
  12. 2026-06-27 03:08 UTCEPSS rescore
  13. 2026-06-27 03:08 UTCEPSS rescore
  14. 2026-06-25 13:49 UTCEPSS rescore
  15. 2026-06-25 13:49 UTCEPSS rescore
  16. 2026-06-23 21:32 UTCEPSS rescore
  17. 2026-06-23 21:32 UTCEPSS rescore
  18. 2026-06-22 14:25 UTCEPSS rescore
  19. 2026-06-22 14:25 UTCEPSS rescore
  20. 2026-06-21 01:59 UTCEPSS rescore
  21. 2026-06-21 01:59 UTCEPSS rescore
  22. 2026-06-18 17:52 UTCEPSS rescore
  23. 2026-06-18 17:52 UTCEPSS rescore
  24. 2026-06-17 23:43 UTCOSV refresh
  25. 2026-06-17 17:52 UTCEPSS rescore
  26. 2026-06-16 17:52 UTCEPSS rescore
  27. 2026-06-16 17:52 UTCEPSS rescore
  28. 2026-06-14 23:17 UTCEPSS rescore
  29. 2026-06-13 23:00 UTCEPSS rescore
  30. 2026-06-12 23:11 UTCEPSS rescore
  31. 2026-06-11 14:00 UTCEPSS rescore
  32. 2026-06-10 22:18 UTCEPSS rescore
  33. 2026-06-10 13:22 UTCEPSS rescore
  34. 2026-06-08 14:16 UTCEPSS rescore
  35. 2026-06-08 14:16 UTCEPSS rescore
  36. 2026-06-07 15:24 UTCEPSS rescore
  37. 2026-06-06 13:47 UTCEPSS rescore
  38. 2026-06-06 13:47 UTCEPSS rescore
  39. 2026-06-05 22:46 UTCEPSS rescore
  40. 2026-06-05 22:46 UTCEPSS rescore
  41. 2026-06-04 13:12 UTCEPSS rescore
  42. 2026-06-04 13:12 UTCEPSS rescore
  43. 2026-06-02 20:12 UTCEPSS rescore
  44. 2026-06-01 13:51 UTCEPSS rescore
  45. 2026-06-01 13:51 UTCEPSS rescore
  46. 2026-05-31 00:16 UTCEPSS rescore
  47. 2026-05-29 20:43 UTCEG score recompute
  48. 2026-05-29 20:43 UTCVendor advisory
  49. 2026-05-29 20:43 UTCGHSA enrichment
  50. 2026-05-29 13:44 UTCEPSS rescore

Related CVEs(same product + same vendor + same CWE)

Frequently asked(5)

What is CVE-2025-39966?
CVE-2025-39966 is a high vulnerability published on October 15, 2025. In the Linux kernel, the following vulnerability has been resolved: iommufd: Fix race during abort for file descriptors fput() doesn't actually call file_operations release() synchronously, it puts the file on a work queue and it will be released eventually. This is normally fine, except for…
When was CVE-2025-39966 disclosed?
CVE-2025-39966 was first published in the National Vulnerability Database on October 15, 2025, with the most recent update on February 26, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2025-39966 actively exploited?
CVE-2025-39966 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 1.1% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2025-39966?
CVE-2025-39966 has a CVSS v3 base score of 7.0 (NVD).
How do I remediate CVE-2025-39966?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2025-39966, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

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