CVE-2025-40094: Linux kernel · usb: gadget: f_acm: Refactor bind path to use __free()
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 7.8 High · fixed in 5.15.0-1110.119~20.04.1 : patch Linux kernel soon.
Data as of 26 Oct 2026, 17:16 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 4% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 5.15.0-1110.119~20.04.1, 5.15.0-1100.109~20.04.1, 5.15.0-1100.107~20.04.2 +2
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 30 Oct 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Upgrade to a fixed release listed under Affected software.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| linux | Affected
| Fixed in
|
AI-suggested
If you cannot patch yet, avoid triggering bind/unbind cycles on the affected USB gadget ACM function if possible.
Description
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
References
- nvd.nist.gov/vuln/detail/CVE-2025-40094 (opens in a new tab)
- git.kernel.org/stable/c/201a66d8e6630762e760e1d78f1d149da1691e7b (opens in a new tab)
- git.kernel.org/stable/c/2b1546f7c5fc6c44555a8e7a2b34229d1dcd2175 (opens in a new tab)
- git.kernel.org/stable/c/47b2116e54b4a854600341487e8b55249e926324 (opens in a new tab)
- git.kernel.org/stable/c/c4301e4dd6b32faccb744f1c2320e64235b68d3b (opens in a new tab)
- git.kernel.org/stable/c/c5d116862dd3ed162d079738a5ebddf9fceea850 (opens in a new tab)
- git.kernel.org/stable/c/e348d18fb0124b662cfefb3001733b49da428215 (opens in a new tab)
- ubuntu.com/security/CVE-2025-40094 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2025-40094 (opens in a new tab)
- git.kernel.org/linus/47b2116e54b4a854600341487e8b55249e926324 (opens in a new tab)
- ubuntu.com/security/notices/USN-8029-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8030-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8033-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8033-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8033-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-8034-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8033-4 (opens in a new tab)
- ubuntu.com/security/notices/USN-8029-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8033-5 (opens in a new tab)
- ubuntu.com/security/notices/USN-8034-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8048-1 (opens in a new tab)