Answer in brief
CVE-2026-68166 records a Unknown severity vulnerability in userfaultfd: prevent registration of special VMAs. The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
A CVSS score is not reported in the current record. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | >=54007f818206dc27309ca423df4c87dd160a7208 <165613191ad9d034bf17c00e3a142f9561597ec5 || >=54007f818206dc27309ca423df4c87dd160a7208 <0c26202b157f1efc3cd2f26f5c30f59b508a6a5d || >=54007f818206dc27309ca423df4c87dd160a7208 <3c58f641e813c3c71039f8fd4d4e2a3aab713288 | 165613191ad9d034bf17c00e3a142f9561597ec5, 0c26202b157f1efc3cd2f26f5c30f59b508a6a5d, 3c58f641e813c3c71039f8fd4d4e2a3aab713288 |
| Linux/Linuxgeneric | 6.6 | Not reported |
Published upstream
Aug 10, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Aug 10, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Aug 10, 2026
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.
Quoted source text, attributed separately from HOL analysis.
Answer in brief
CVE-2026-68166 records a Unknown severity vulnerability in userfaultfd: prevent registration of special VMAs. The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
A CVSS score is not reported in the current record. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | >=54007f818206dc27309ca423df4c87dd160a7208 <165613191ad9d034bf17c00e3a142f9561597ec5 || >=54007f818206dc27309ca423df4c87dd160a7208 <0c26202b157f1efc3cd2f26f5c30f59b508a6a5d || >=54007f818206dc27309ca423df4c87dd160a7208 <3c58f641e813c3c71039f8fd4d4e2a3aab713288 | 165613191ad9d034bf17c00e3a142f9561597ec5, 0c26202b157f1efc3cd2f26f5c30f59b508a6a5d, 3c58f641e813c3c71039f8fd4d4e2a3aab713288 |
| Linux/Linuxgeneric | 6.6 | Not reported |
Published upstream
Aug 10, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Aug 10, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Aug 10, 2026
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.
Quoted source text, attributed separately from HOL analysis.