NVD / CVE Program· CNA Linux

CVE-2025-39945: cnic: Fix use-after-free bugs in cnic_delete_task

HighCVSS 7.8 · v3.1—No exploit Fix available

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: 0.16% (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 0405055930264ea8fd26f4131466fa7652e5e47d, 0627e1481676669cae2df0d85b5ff13e7d24c390, 6e33a7eed587062ca8161ad1f4584882a860d697; azl3 kernel 6.6.104.2-4 on Azure Linux 3.0 6.6.112.1-1.

Low priority for now. Upgrade to Linux Linux 0405055930264ea8fd26f4131466fa7652e5e47d, 0627e1481676669cae2df0d85b5ff13e7d24c390, 6e33a7eed587062ca8161ad1f4584882a860d697; azl3 kernel 6.6.104.2-4 on Azure Linux 3.0 6.6.112.1-1 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: cnic: Fix use-after-free bugs in cnic_delete_task The original code uses cancel_delayed_work() in cnic_cm_stop_bnx2x_hw(), which does not guarantee that the delayed work item 'delete_task' has fully completed if it was already running. Additionally, the delayed work item is cyclic, the flush_workqueue() in cnic_cm_stop_bnx2x_hw() only blocks and waits for work items that were already queued to the workqueue prior to its invocation. Any work items submitted after flush_workqueue() is called are not included in the set of tasks that the flush operation awaits. This means that after the cyclic work items have finished executing, a delayed work item may still exist in the workqueue. This leads to use-after-free scenarios where the cnic_dev is deallocated by cnic_free_dev(), while delete_task remains active and attempt to dereference cnic_dev in cnic_delete_task(). A typical race condition is illustrated below: CPU 0 (cleanup) | CPU 1 (delayed work callback) cnic_netdev_event() | cnic_stop_hw() | cnic_delete_task() cnic_cm_stop_bnx2x_hw() | ... cancel_delayed_work() | /* the queue_delayed_work() flush_workqueue() | executes after flush_workqueue()*/ | queue_delayed_work() cnic_free_dev(dev)//free | cnic_delete_task() //new instance | dev = cp->dev; //use Replace cancel_delayed_work() with cancel_delayed_work_sync() to ensure that the cyclic delayed work item is properly canceled and that any ongoing execution of the work item completes before the cnic_dev is deallocated. Furthermore, since cancel_delayed_work_sync() uses __flush_work(work, true) to synchronously wait for any currently executing instance of the work item to finish, the flush_workqueue() becomes redundant and should be removed. This bug was identified through static analysis. To reproduce the issue and validate the fix, I simulated the cnic PCI device in QEMU and introduced intentional delays — such as inserting calls to ssleep() within the cnic_delete_task() function — to increase the likelihood of triggering the bug.

Memory safety

Published: Oct 4, 2025
Updated: Oct 19, 2026
EPSS: 0.1% · 5th percentile
CWE: CWE-416

Report tools

JSON

Action score

Monitor

Low priority for now.

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

CISA SSVC decision

Exploitation: none
Automatable: no
Technical impact: total

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD: 7.8
CNA · Linux: 7.8; agree

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

Not in KEV: no record of exploitation in the wild
No public exploit code on record
A fix has been released

If any of these changes, we'll tell you in the daily email digest.

Is your version affected? Check it

Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

We use this product, ask for help

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

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
- 2.6.37affected
- fdf24086f4752aee5dfb40143c736250df017820 and later · before fde6e73189f40ebcf0633aed2b68e731c25f3aa3affected · git
- fdf24086f4752aee5dfb40143c736250df017820 and later · before 7b6a5b0a6b392263c3767fc945b311ea04b34bbdaffected · git
- fdf24086f4752aee5dfb40143c736250df017820 and later · before 0405055930264ea8fd26f4131466fa7652e5e47daffected · git
- fdf24086f4752aee5dfb40143c736250df017820 and later · before e1fcd4a9c09feac0902a65615e866dbf22616125affected · git
- fdf24086f4752aee5dfb40143c736250df017820 and later · before 8eeb2091e72d75df8ceaa2172638d61b4cf8929aaffected · git
- fdf24086f4752aee5dfb40143c736250df017820 and later · before 6e33a7eed587062ca8161ad1f4584882a860d697affected · git
- fdf24086f4752aee5dfb40143c736250df017820 and later · before 0627e1481676669cae2df0d85b5ff13e7d24c390affected · git
- fdf24086f4752aee5dfb40143c736250df017820 and later · before cfa7d9b1e3a8604afc84e9e51d789c29574fb216affected · git
- before 2.6.37not affected · semver

Affected versions · NVD (8)

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

linux linux kernel2.6.37 and later · before 5.4.300
linux linux kernel5.5 and later · before 5.10.245
linux linux kernel5.11 and later · before 5.15.194
linux linux kernel5.16 and later · before 6.1.154
linux linux kernel6.2 and later · before 6.6.108
linux linux kernel6.7 and later · before 6.12.49
linux linux kernel6.13 and later · before 6.16.9
linux linux kernel6.17

Package-level exposure

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

Ecosystem	Package	Affected range	Fix
Debian:11	linux	before 5.10.247-1	5.10.247-1
Debian:11	linux-6.1	before 6.1.158-1~deb11u1	6.1.158-1~deb11u1
Debian:12	linux	before 6.1.158-1	6.1.158-1
Debian:13	linux	before 6.12.57-1	6.12.57-1
Debian:14	linux	before 6.16.9-1	6.16.9-1

Same product

linux: all records

Other highest-scoring records for the same primary product.

CVE-2026-31431crypto: algif_aead - Revert to operating out-of-placeKEV
90Now
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
89Now
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-2025-39943Oct 4, 2025 · ksmbd: smbdirect: validate data_offset and data_length field of smb_direct_data_transfer
28Monitor
← EarlierCVE-2025-39944Oct 4, 2025 · octeontx2-pf: Fix use-after-free bugs in otx2_sync_tstamp()
31Monitor
Later →CVE-2025-39946Oct 4, 2025 · tls: make sure to abort the stream if headers are bogus
25Monitor

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	0405055930264ea8fd26f4131466fa7652e5e47d	Vendor (CNA)
Linux Linux	0627e1481676669cae2df0d85b5ff13e7d24c390	Vendor (CNA)
Linux Linux	6e33a7eed587062ca8161ad1f4584882a860d697	Vendor (CNA)
Linux Linux	7b6a5b0a6b392263c3767fc945b311ea04b34bbd	Vendor (CNA)
Linux Linux	8eeb2091e72d75df8ceaa2172638d61b4cf8929a	Vendor (CNA)
Linux Linux	cfa7d9b1e3a8604afc84e9e51d789c29574fb216	Vendor (CNA)
Linux Linux	e1fcd4a9c09feac0902a65615e866dbf22616125	Vendor (CNA)
Linux Linux	fde6e73189f40ebcf0633aed2b68e731c25f3aa3	Vendor (CNA)
azl3 kernel 6.6.104.2-4 on Azure Linux 3.0	6.6.112.1-1 · CBL-Mariner Releases	Microsoft (MSRC)
debian:linux	6.1.158-1 · Debian:12	Package registry (OSV)
debian:linux-6.1	6.1.158-1~deb11u1 · Debian:11	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.

Not on record for this CVE: EPSS history · patch commit or PR link · researcher credit · variant or chain candidate · public bounty program.

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 (1)

Fix✗ → ✓Sep 28, 2026, 10:10 PM UTC

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

References

git.kernel.org/stable/c/0405055930264ea8fd26f4131466fa7652e5e47d

Show all references (7 more)

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

All records