NVD / CVE Program· CNA Linux

CVE-2025-39871: dmaengine: idxd: Remove improper idxd_free

Noroxi assessment

Priority: Monitor (action score 31/100)

The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
Probability of exploitation in the next 30 days: 0.15% (FIRST EPSS).
Someone with local access to the system can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
Fixed version: Linux Linux 0e95ee7f532b21206fe3f1c4054002b0d21e3b9c, 24414bbcb37e1af95190af36c21ae51d497e1a9e, 6.1.160.

Low priority for now. Upgrade to Linux Linux 0e95ee7f532b21206fe3f1c4054002b0d21e3b9c, 24414bbcb37e1af95190af36c21ae51d497e1a9e, 6.1.160 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

In the Linux kernel, the following vulnerability has been resolved: dmaengine: idxd: Remove improper idxd_free The call to idxd_free() introduces a duplicate put_device() leading to a reference count underflow: refcount_t: underflow; use-after-free. WARNING: CPU: 15 PID: 4428 at lib/refcount.c:28 refcount_warn_saturate+0xbe/0x110 ... Call Trace: <TASK> idxd_remove+0xe4/0x120 [idxd] pci_device_remove+0x3f/0xb0 device_release_driver_internal+0x197/0x200 driver_detach+0x48/0x90 bus_remove_driver+0x74/0xf0 pci_unregister_driver+0x2e/0xb0 idxd_exit_module+0x34/0x7a0 [idxd] __do_sys_delete_module.constprop.0+0x183/0x280 do_syscall_64+0x54/0xd70 entry_SYSCALL_64_after_hwframe+0x76/0x7e The idxd_unregister_devices() which is invoked at the very beginning of idxd_remove(), already takes care of the necessary put_device() through the following call path: idxd_unregister_devices() -> device_unregister() -> put_device() In addition, when CONFIG_DEBUG_KOBJECT_RELEASE is enabled, put_device() may trigger asynchronous cleanup via schedule_delayed_work(). If idxd_free() is called immediately after, it can result in a use-after-free. Remove the improper idxd_free() to avoid both the refcount underflow and potential memory corruption during module unload.

HighCVSS 7.8 · v3.1—No exploit Fix available

Memory safety

BDU:2025-13887

Published: Sep 23, 2025
Updated: Oct 19, 2026
EPSS: 0.1% · 4th percentile
CWE: CWE-416

Report tools

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Action score

Monitor

Low priority for now.

CVSS: 31 / 40 · 7.8 / 10
CISA KEV: 0 / 30 · Not listed
EPSS: 0 / 30 · 0.1%

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No public exploit code on record
A fix has been released

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Noroxi analysis

What does it mean in your environment?

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

Vendor	Product	CPE
linux	linux kernel	cpe:2.3:o:linux:linux_kernel

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

linux linux kernel6.1.140 and later · before 6.2
linux linux kernel6.6.92 and later · before 6.6.107
linux linux kernel6.12.30 and later · before 6.12.48
linux linux kernel6.14.8 and later · before 6.15
linux linux kernel6.15.1 and later · before 6.16.8
linux linux kernel6.15
linux linux kernel6.17

Versions reported by the vendor

Affected version ranges reported by the assigning authority (Linux). Independent of NVD's CPE analysis and usually ahead of it.

Linux Linux
- 2b7a961cea0e5b65afda911f76d14fec5c98d024, 6.15affected
- 68ac5a01f635b3791196fd1c39bc48497252c36f and later · before 24414bbcb37e1af95190af36c21ae51d497e1a9eaffected · git
- d2d05fd0fc95c4defed6f7b87550e20e8baa1d97 and later · before 0e95ee7f532b21206fe3f1c4054002b0d21e3b9caffected · git
- 21f9f5cd9a0c75084d4369ba0b8c4f695c41dea7 and later · before dd7a7e43269711d757fc260b0bbdf7138f75de11affected · git
- d5449ff1b04dfe9ed8e455769aa01e4c2ccf6805 and later · before da4fbc1488a4cec6748da685181ee4449a878dacaffected · git
- d5449ff1b04dfe9ed8e455769aa01e4c2ccf6805 and later · before f41c538881eec4dcf5961a242097d447f848cda6affected · git
- 6.1.140 and later · before 6.1.160affected · semver
- 6.6.92 and later · before 6.6.107affected · semver
- 6.12.30 and later · before 6.12.48affected · semver
- 6.14.8 and later · before 6.15affected · semver

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

Ecosystem	Package	Affected range	Fix
Debian:12	linux	before 6.1.162-1	6.1.162-1
Debian:13	linux	before 6.12.48-1	6.12.48-1
Debian:14	linux	before 6.16.8-1	6.16.8-1

Same product

linux: all records

Other highest-scoring records for the same primary product.

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CVE-2022-0847A flaw was found in the way the "flags" member of the new pipe buffer structure was lacking proper initialization in copy_page_to_iter_pipe KEV
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CVE-2021-22555Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACEKEV
85Now

Published before and after this one in the same product

← EarlierCVE-2025-39869Sep 23, 2025 · dmaengine: ti: edma: Fix memory allocation size for queue_priority_map
28Monitor
← EarlierCVE-2025-39870Sep 23, 2025 · dmaengine: idxd: Fix double free in idxd_setup_wqs()
31Monitor
Later →CVE-2025-39872Sep 23, 2025 · hsr: hold rcu and dev lock for hsr_get_port_ndev
22Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / package	Fixed version	Source
Linux Linux	0e95ee7f532b21206fe3f1c4054002b0d21e3b9c	Vendor (CNA)
Linux Linux	24414bbcb37e1af95190af36c21ae51d497e1a9e	Vendor (CNA)
Linux Linux	6.1.160	Vendor (CNA)
Linux Linux	6.12.48	Vendor (CNA)
Linux Linux	6.15	Vendor (CNA)
Linux Linux	6.6.107	Vendor (CNA)
Linux Linux	da4fbc1488a4cec6748da685181ee4449a878dac	Vendor (CNA)
Linux Linux	dd7a7e43269711d757fc260b0bbdf7138f75de11	Vendor (CNA)
Linux Linux	f41c538881eec4dcf5961a242097d447f848cda6	Vendor (CNA)
debian:linux	6.1.162-1 · Debian:12	Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

No history yet (it accumulates with the daily EPSS job).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

Someone with local access to the system can trigger it.
A low-privileged account is enough.
No user action is required.
No special conditions are required; it is repeatable.

If successful

Confidentiality: high · data can be read
Integrity: high · data or configuration can be modified
Availability: high · the service can be disrupted

Attack vector: Local
Attack complexity: Low
Privileges required: Low
User interaction: None
Scope: Unchanged
Confidentiality impact: High
Integrity impact: High
Availability impact: High

Weakness class (CWE)

CWE-416 · Use After Free

CVSS vector

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

nvd-primary

Root cause

After a memory region is freed, another reference pointing to it is still used. By then, the same region may have been allocated for different data.

The bug in code

The whole CWE-416 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

1free(dev->buf);
2/* ... another thread is still running ... */
3process(dev->buf);

Fixed

1lock(&dev->lock);
2free(dev->buf);
3dev->buf = NULL;
4unlock(&dev->lock);

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

Fix✗ → ✓Sep 28, 2026, 10:10 PM UTC

For records you follow, these changes also arrive as notifications. →

References

git.kernel.org/stable/c/0e95ee7f532b21206fe3f1c4054002b0d21e3b9c

Show all references (6 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

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