CVE-2026-68166userfaultfd: prevent registration of special VMAs
Updated under an hour ago ()
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No exploitation reported and no EPSS estimate yet.
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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.
- CVSS
- Not yet scored
- Weakness (CWE)
- Not given
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- Linux
- NVD analysis
- Received
- Record last updated
- Aug 23, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
Linux Linux linux:linux (from the name) | from 54007f818206dc27309ca423df4c87dd160a7208 before d974b4b786214883bd8e56bda10b454c80fd6205; 54007f818206dc27309ca423df4c87dd160a7208 builds before 495a28d5a100be1b232633f4c2dcc42ba10b3796; from 54007f818206dc27309ca423df4c87dd160a7208 before 165613191ad9d034bf17c00e3a142f9561597ec5; 54007f818206dc27309ca423df4c87dd160a7208 builds before 0c26202b157f1efc3cd2f26f5c30f59b508a6a5d; 54007f818206dc27309ca423df4c87dd160a7208 builds before 3c58f641e813c3c71039f8fd4d4e2a3aab713288 | CNA record |
References
- https://git.kernel.org/stable/c/d974b4b786214883bd8e56bda10b454c80fd6205
- https://git.kernel.org/stable/c/495a28d5a100be1b232633f4c2dcc42ba10b3796
- https://git.kernel.org/stable/c/165613191ad9d034bf17c00e3a142f9561597ec5
- https://git.kernel.org/stable/c/0c26202b157f1efc3cd2f26f5c30f59b508a6a5d
- https://git.kernel.org/stable/c/3c58f641e813c3c71039f8fd4d4e2a3aab713288
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.