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NVD / CVE Program· CNA Linux

CVE-2025-40094: usb: gadget: f_acm: Refactor bind path to use __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 201a66d8e6630762e760e1d78f1d149da1691e7b, 2b1546f7c5fc6c44555a8e7a2b34229d1dcd2175, 47b2116e54b4a854600341487e8b55249e926324.

Low priority for now. Upgrade to Linux Linux 201a66d8e6630762e760e1d78f1d149da1691e7b, 2b1546f7c5fc6c44555a8e7a2b34229d1dcd2175, 47b2116e54b4a854600341487e8b55249e926324 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: usb: gadget: f_acm: Refactor bind path to use __free() After an bind/unbind cycle, the acm->notify_req is left stale. If a subsequent bind fails, the unified error label attempts to free this stale request, leading to a NULL pointer dereference when accessing ep->ops->free_request. Refactor the error handling in the bind path to use the __free() automatic cleanup mechanism. Unable to handle kernel NULL pointer dereference at virtual address 0000000000000020 Call trace: usb_ep_free_request+0x2c/0xec gs_free_req+0x30/0x44 acm_bind+0x1b8/0x1f4 usb_add_function+0xcc/0x1f0 configfs_composite_bind+0x468/0x588 gadget_bind_driver+0x104/0x270 really_probe+0x190/0x374 __driver_probe_device+0xa0/0x12c driver_probe_device+0x3c/0x218 __device_attach_driver+0x14c/0x188 bus_for_each_drv+0x10c/0x168 __device_attach+0xfc/0x198 device_initial_probe+0x14/0x24 bus_probe_device+0x94/0x11c device_add+0x268/0x48c usb_add_gadget+0x198/0x28c dwc3_gadget_init+0x700/0x858 __dwc3_set_mode+0x3cc/0x664 process_scheduled_works+0x1d8/0x488 worker_thread+0x244/0x334 kthread+0x114/0x1bc ret_from_fork+0x10/0x20

HighCVSS 7.8 · v3.1—No exploit Fix available
Published
Oct 30, 2025
Updated
Oct 19, 2026
EPSS
0.1% · 4th percentile
CWE
—

Report tools

JSON

Action score

31

Monitor

Low priority for now.

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

CNA vs NVD score

NVD
—
CNA · Linux
7.8
NVD has not scored this yet; the score shown is the CNA’s.

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

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When you'll hear from us

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  • when exploit code appears or is weaponized
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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.

—

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

    • 2.6.27affected
    • 1f1ba11b64947051fc32aa15fcccef6463b433f7 and later · before c5d116862dd3ed162d079738a5ebddf9fceea850affected · git
    • 1f1ba11b64947051fc32aa15fcccef6463b433f7 and later · before 2b1546f7c5fc6c44555a8e7a2b34229d1dcd2175affected · git
    • 1f1ba11b64947051fc32aa15fcccef6463b433f7 and later · before e348d18fb0124b662cfefb3001733b49da428215affected · git
    • 1f1ba11b64947051fc32aa15fcccef6463b433f7 and later · before 201a66d8e6630762e760e1d78f1d149da1691e7baffected · git
    • 1f1ba11b64947051fc32aa15fcccef6463b433f7 and later · before c4301e4dd6b32faccb744f1c2320e64235b68d3baffected · git
    • 1f1ba11b64947051fc32aa15fcccef6463b433f7 and later · before 47b2116e54b4a854600341487e8b55249e926324affected · git
    • before 2.6.27not affected · semver
    • 5.15.196 and later · up to and including 5.15.*not affected · semver
    • 6.1.158 and later · up to and including 6.1.*not affected · semver

Package-level exposure

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

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 6.1.158-16.1.158-1
Debian:13linuxbefore 6.12.57-16.12.57-1
Debian:14linuxbefore 6.17.6-16.17.6-1

Same product

linux: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-74705udp: fix potential use-after-free in tunnel segmentation
    40Plan
  • CVE-2026-74612veth: fix skb length accounting after XDP frag adjustment
    40Plan
  • CVE-2026-74475vxlan: use neigh_ha_snapshot() in route_shortcircuit()
    40Plan

Published before and after this one in the same product

  • ← EarlierCVE-2025-40092Oct 30, 2025 · usb: gadget: f_ncm: Refactor bind path to use __free()
    31Monitor
  • ← EarlierCVE-2025-40093Oct 30, 2025 · usb: gadget: f_ecm: Refactor bind path to use __free()
    31Monitor
  • Later →CVE-2025-40095Oct 30, 2025 · usb: gadget: f_rndis: Refactor bind path to use __free()
    31Monitor

Remediation

Which version to upgrade to

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

Product / packageFixed versionSource
Linux Linux201a66d8e6630762e760e1d78f1d149da1691e7bVendor (CNA)
Linux Linux2b1546f7c5fc6c44555a8e7a2b34229d1dcd2175Vendor (CNA)
Linux Linux47b2116e54b4a854600341487e8b55249e926324Vendor (CNA)
Linux Linuxc4301e4dd6b32faccb744f1c2320e64235b68d3bVendor (CNA)
Linux Linuxc5d116862dd3ed162d079738a5ebddf9fceea850Vendor (CNA)
Linux Linuxe348d18fb0124b662cfefb3001733b49da428215Vendor (CNA)
debian:linux6.1.158-1 · Debian:12Package 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)

—

CVSS vector

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

nvd-secondary

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✗ → ✓

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

References

Show all references (5 more)

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

All records