CVE-2026-64331: Linux kernel · usbip: vudc: fix NULL deref in vep_dequeue()
Affects Linux kernelSource CVE Database V5
Not known to be exploited · fixed in d0ebf9cc7c2ddf95a7cfc654b940bdacb7edde97 : update Linux kernel when convenient.
Data as of 6 Nov 2026, 17:19 UTC
Rated by Threat Radar · No CVSS score from NVD or the CNA
Thin evidence
One scorer or none- CISA SSVC
- Exploitation
- No evidence of active exploitation and no public proof of concept
- Automatable
- Attackers cannot reliably automate steps 1–4 of the kill chain
- Technical impact
- Limited control over the software or limited information exposure
CISA SSVC assessment, 2026-11-06.
- Patch
- Available – fixed in d0ebf9cc7c2ddf95a7cfc654b940bdacb7edde97, c5371e0b91b24159a3ebaa61e70b0980bcf03c0a, 0025276175fbbe0dcbf3f84d090b0adee769e9d9 +5
Exploitation evidence
Disclosed: evidence found.
CVE published 25 Jul 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: 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 6 Nov 2026.
What to do
Upgrade to a fixed release listed under Affected software.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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Description
In the Linux kernel, the following vulnerability has been resolved: usbip: vudc: fix NULL deref in vep_dequeue() vep_alloc_request() wasn't initializing vrequest->udc, so cancellations on the FunctionFS AIO path were arriving in vep_dequeue without a valid UDC reference. Since vrequest->udc is never actually properly used anywhere, we opt to remove it, and update vep_dequeue to obtain a reference to the udc with ep_to_vudc(), consistent with the other vep_ ops. AFAICT this bug has existed for ~10 years. Seems that nobody has really stressed the FunctionFS AIO path on usbip's vudc. I tested this fix in a QEMU aarch64 guest driving FunctionFS endpoints via AIO. Before the fix, running `usbip attach` from the host would cause the guest to oops with the following backtrace: Call trace: vep_dequeue+0x1c/0xe4 (P) usb_ep_dequeue+0x14/0x20 ffs_aio_cancel+0x24/0x34 __arm64_sys_io_cancel+0xb0/0x124 do_el0_svc+0x68/0x100 el0_svc+0x18/0x5c el0t_64_sync_handler+0x98/0xdc el0t_64_sync+0x154/0x158
References
- git.kernel.org/stable/c/9858c91d9ee6a13c45311569039413729fc9b757 (opens in a new tab)
- git.kernel.org/stable/c/1226293ec9bed3d4cc5b05eeeb811d315ca51652 (opens in a new tab)
- git.kernel.org/stable/c/3750f75f29f99c0223601e2ee73ad084adec47bd (opens in a new tab)
- git.kernel.org/stable/c/d0ebf9cc7c2ddf95a7cfc654b940bdacb7edde97 (opens in a new tab)
- git.kernel.org/stable/c/0025276175fbbe0dcbf3f84d090b0adee769e9d9 (opens in a new tab)
- git.kernel.org/stable/c/347b59e9f96719d89b6ef555d02a18ada1a5846f (opens in a new tab)
- git.kernel.org/stable/c/0443e4416aa1ee97748d1ed904eaf3352c60045e (opens in a new tab)
- git.kernel.org/stable/c/c5371e0b91b24159a3ebaa61e70b0980bcf03c0a (opens in a new tab)