Answer in brief
CVE-2026-31575 records a Unknown severity vulnerability in mm/userfaultfd: fix hugetlb fault mutex hash calculation. 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 | >=a08c7193e4f18dc8508f2d07d0de2c5b94cb39a3 <5a525c43baaba0bf3063f86996ca3623b71e4172 || >=a08c7193e4f18dc8508f2d07d0de2c5b94cb39a3 <574501ede47ac439afd67ba9812bc66722d500ba || >=a08c7193e4f18dc8508f2d07d0de2c5b94cb39a3 <08282b1bf74c69fc8ecd25493e7fdb5460f01290 || >=a08c7193e4f18dc8508f2d07d0de2c5b94cb39a3 <f4689fc089765d36c026063fb22d23533e883eb6 || >=a08c7193e4f18dc8508f2d07d0de2c5b94cb39a3 <0217c7fb4de4a40cee667eb21901f3204effe5ac | 5a525c43baaba0bf3063f86996ca3623b71e4172, 574501ede47ac439afd67ba9812bc66722d500ba, 08282b1bf74c69fc8ecd25493e7fdb5460f01290, f4689fc089765d36c026063fb22d23533e883eb6, 0217c7fb4de4a40cee667eb21901f3204effe5ac |
| Linux/Linuxgeneric | 6.7 | Not reported |
Published upstream
Apr 24, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Nov 5, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Nov 5, 2026
In the Linux kernel, the following vulnerability has been resolved: mm/userfaultfd: fix hugetlb fault mutex hash calculation In mfill_atomic_hugetlb(), linear_page_index() is used to calculate the page index for hugetlb_fault_mutex_hash(). However, linear_page_index() returns the index in PAGE_SIZE units, while hugetlb_fault_mutex_hash() expects the index in huge page units. This mismatch means that different addresses within the same huge page can produce different hash values, leading to the use of different mutexes for the same huge page. This can cause races between faulting threads, which can corrupt the reservation map and trigger the BUG_ON in resv_map_release(). Fix this by introducing hugetlb_linear_page_index(), which returns the page index in huge page granularity, and using it in place of linear_page_index().
Quoted source text, attributed separately from HOL analysis.