Description
In the Linux kernel, the following vulnerability has been resolved:
userfaultfd: prevent registration of special VMAs
Vova Tokarev says:
userfaultfd allows registration on shadow stack VMAs. With userfaultfd access, you can register on the shadow stack, discard a page ... and inject a page with chosen return addresses via UFFDIO_COPY.
Update vma_can_userfault() to reject VM_SHADOW_STACK.
While on it, also reject VM_SPECIAL so that if a driver would implement vm_uffd_ops, it wouldn't be possible to register special VMAs with userfaultfd.
Since VM_SPECIAL includes VM_DONTEXPAND which is set but hugetlb, exclude hugetlb VMAs from the check for VM_SPECIAL.
Metrics
No CVSS score has been published yet.
Affected software
Source: the vendor's advisory (CNA). NVD analysis pending.
| Vendor | Product | Versions |
|---|---|---|
| Linux | Linux | >= 54007f818206dc27309ca423df4c87dd160a7208, < d974b4b786214883bd8e56bda10b454c80fd6205; >= 54007f818206dc27309ca423df4c87dd160a7208, < 495a28d5a100be1b232633f4c2dcc42ba10b3796; >= 54007f818206dc27309ca423df4c87dd160a7208, < 165613191ad9d034bf17c00e3a142f9561597ec5; >= 54007f818206dc27309ca423df4c87dd160a7208, < 0c26202b157f1efc3cd2f26f5c30f59b508a6a5d; >= 54007f818206dc27309ca423df4c87dd160a7208, < 3c58f641e813c3c71039f8fd4d4e2a3aab713288 |
| Linux | Linux | 6.6 |
References
- https://git.kernel.org/stable/c/0c26202b157f1efc3cd2f26f5c30f59b508a6a5d
- https://git.kernel.org/stable/c/165613191ad9d034bf17c00e3a142f9561597ec5
- https://git.kernel.org/stable/c/3c58f641e813c3c71039f8fd4d4e2a3aab713288
- https://git.kernel.org/stable/c/495a28d5a100be1b232633f4c2dcc42ba10b3796
- https://git.kernel.org/stable/c/d974b4b786214883bd8e56bda10b454c80fd6205
Timeline
- Published
- Aug 10, 2026
- Last modified
- Nov 6, 2026
- NVD status
- Received