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Vulnerability · Published Apr 24, 2026 · Assigned by Linux

CVE-2026-31575mm/userfaultfd: fix hugetlb fault mutex hash calculation

Medium 5.5

In plain English

A medium-severity security flaw in Linux from Linux. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.1% (higher than 2% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS NVD)5.5Medium
Exploit odds (30 days)0.1%top 98.0% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official description

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().

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:13linux6.12.85-1DEBIAN-CVE-2026-31575
Debian:14linux6.19.14-1DEBIAN-CVE-2026-31575
Ubuntu:24.04:LTSlinux6.8.0-136.136UBUNTU-CVE-2026-31575
Ubuntu:25.10linuxno fix listedUBUNTU-CVE-2026-31575
Ubuntu:26.04:LTSlinux7.0.0-27.27USN-8488-1
Ubuntu:26.04:LTSlinux7.0.0-27.27UBUNTU-CVE-2026-31575
Ubuntu:22.04:LTSlinux-allwinner-5.19no fix listedUBUNTU-CVE-2026-31575
Ubuntu:24.04:LTSlinux-aws6.8.0-1061.64UBUNTU-CVE-2026-31575
Ubuntu:25.10linux-awsno fix listedUBUNTU-CVE-2026-31575
Ubuntu:26.04:LTSlinux-aws7.0.0-1008.8USN-8488-1
Ubuntu:26.04:LTSlinux-aws7.0.0-1008.8UBUNTU-CVE-2026-31575
Ubuntu:22.04:LTSlinux-aws-5.19no fix listedUBUNTU-CVE-2026-31575
Ubuntu:24.04:LTSlinux-aws-6.14no fix listedUBUNTU-CVE-2026-31575
Ubuntu:24.04:LTSlinux-aws-6.17no fix listedUBUNTU-CVE-2026-31575
Ubuntu:22.04:LTSlinux-aws-6.2no fix listedUBUNTU-CVE-2026-31575
Ubuntu:22.04:LTSlinux-aws-6.5no fix listedUBUNTU-CVE-2026-31575
Ubuntu:22.04:LTSlinux-aws-6.86.8.0-1061.64~22.04.1UBUNTU-CVE-2026-31575
Ubuntu:24.04:LTSlinux-azure6.8.0-1063.71UBUNTU-CVE-2026-31575
Ubuntu:25.10linux-azureno fix listedUBUNTU-CVE-2026-31575
Ubuntu:26.04:LTSlinux-azure7.0.0-1010.10UBUNTU-CVE-2026-31575
Ubuntu:26.04:LTSlinux-azure7.0.0-1010.10USN-8603-1
Ubuntu:22.04:LTSlinux-azure-5.19no fix listedUBUNTU-CVE-2026-31575
Ubuntu:24.04:LTSlinux-azure-6.11no fix listedUBUNTU-CVE-2026-31575
Ubuntu:24.04:LTSlinux-azure-6.14no fix listedUBUNTU-CVE-2026-31575
Ubuntu:24.04:LTSlinux-azure-6.17no fix listedUBUNTU-CVE-2026-31575
Ubuntu:22.04:LTSlinux-azure-6.2no fix listedUBUNTU-CVE-2026-31575
Ubuntu:22.04:LTSlinux-azure-6.5no fix listedUBUNTU-CVE-2026-31575
Ubuntu:22.04:LTSlinux-azure-6.86.8.0-1063.71~22.04.1UBUNTU-CVE-2026-31575
Ubuntu:24.04:LTSlinux-azure-fde6.8.0-1062.69UBUNTU-CVE-2026-31575
Ubuntu:25.10linux-azure-fdeno fix listedUBUNTU-CVE-2026-31575
Ubuntu:26.04:LTSlinux-azure-fde7.0.0-1009.9UBUNTU-CVE-2026-31575
Ubuntu:26.04:LTSlinux-azure-fde7.0.0-1009.9USN-8603-1
Ubuntu:22.04:LTSlinux-azure-fde-5.19no fix listedUBUNTU-CVE-2026-31575
Ubuntu:24.04:LTSlinux-azure-fde-6.14no fix listedUBUNTU-CVE-2026-31575
Ubuntu:22.04:LTSlinux-azure-fde-6.2no fix listedUBUNTU-CVE-2026-31575
Ubuntu:22.04:LTSlinux-azure-fde-6.86.8.0-1062.69~22.04.1UBUNTU-CVE-2026-31575
Ubuntu:24.04:LTSlinux-azure-nvidiano fix listedUBUNTU-CVE-2026-31575
Ubuntu:24.04:LTSlinux-azure-nvidia-6.14no fix listedUBUNTU-CVE-2026-31575
Ubuntu:24.04:LTSlinux-gcp6.8.0-1064.72UBUNTU-CVE-2026-31575
Ubuntu:25.10linux-gcpno fix listedUBUNTU-CVE-2026-31575
Ubuntu:26.04:LTSlinux-gcp7.0.0-1007.7UBUNTU-CVE-2026-31575
Ubuntu:26.04:LTSlinux-gcp7.0.0-1007.7USN-8488-1
Ubuntu:22.04:LTSlinux-gcp-5.19no fix listedUBUNTU-CVE-2026-31575
Ubuntu:24.04:LTSlinux-gcp-6.11no fix listedUBUNTU-CVE-2026-31575
Ubuntu:24.04:LTSlinux-gcp-6.14no fix listedUBUNTU-CVE-2026-31575
Ubuntu:24.04:LTSlinux-gcp-6.17no fix listedUBUNTU-CVE-2026-31575
Ubuntu:22.04:LTSlinux-gcp-6.2no fix listedUBUNTU-CVE-2026-31575
Ubuntu:22.04:LTSlinux-gcp-6.5no fix listedUBUNTU-CVE-2026-31575
Ubuntu:22.04:LTSlinux-gcp-6.86.8.0-1064.72~22.04.1UBUNTU-CVE-2026-31575
Ubuntu:24.04:LTSlinux-gke6.8.0-1059.67UBUNTU-CVE-2026-31575
Ubuntu:24.04:LTSlinux-gkeop6.8.0-1046.50UBUNTU-CVE-2026-31575
Ubuntu:22.04:LTSlinux-hwe-5.19no fix listedUBUNTU-CVE-2026-31575
Ubuntu:24.04:LTSlinux-hwe-6.11no fix listedUBUNTU-CVE-2026-31575
Ubuntu:24.04:LTSlinux-hwe-6.14no fix listedUBUNTU-CVE-2026-31575
Ubuntu:24.04:LTSlinux-hwe-6.17no fix listedUBUNTU-CVE-2026-31575
Ubuntu:22.04:LTSlinux-hwe-6.2no fix listedUBUNTU-CVE-2026-31575
Ubuntu:22.04:LTSlinux-hwe-6.5no fix listedUBUNTU-CVE-2026-31575
Ubuntu:22.04:LTSlinux-hwe-6.86.8.0-136.136~22.04.1UBUNTU-CVE-2026-31575
Ubuntu:24.04:LTSlinux-hwe-7.07.0.0-28.28~24.04.1UBUNTU-CVE-2026-31575
Ubuntu:24.04:LTSlinux-hwe-7.07.0.0-28.28~24.04.1USN-8569-1
Ubuntu:24.04:LTSlinux-ibm6.8.0-1061.62UBUNTU-CVE-2026-31575
Ubuntu:26.04:LTSlinux-ibm7.0.0-1009.9UBUNTU-CVE-2026-31575
Ubuntu:26.04:LTSlinux-ibm7.0.0-1009.9USN-8488-1
Ubuntu:22.04:LTSlinux-ibm-6.86.8.0-1061.62~22.04.1UBUNTU-CVE-2026-31575
Ubuntu:22.04:LTSlinux-intel-iot-realtimeno fix listedUBUNTU-CVE-2026-31575
Ubuntu:24.04:LTSlinux-lowlatency6.8.0-136.136.2UBUNTU-CVE-2026-31575
Ubuntu:22.04:LTSlinux-lowlatency-hwe-5.19no fix listedUBUNTU-CVE-2026-31575
Ubuntu:24.04:LTSlinux-lowlatency-hwe-6.11no fix listedUBUNTU-CVE-2026-31575
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.2no fix listedUBUNTU-CVE-2026-31575
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.5no fix listedUBUNTU-CVE-2026-31575
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.86.8.0-136.136.2~22.04.1UBUNTU-CVE-2026-31575
Ubuntu:24.04:LTSlinux-nvidia6.8.0-1059.62UBUNTU-CVE-2026-31575
Ubuntu:26.04:LTSlinux-nvidia7.0.0-1013.13UBUNTU-CVE-2026-31575
Ubuntu:26.04:LTSlinux-nvidia7.0.0-1013.13USN-8507-1
Ubuntu:24.04:LTSlinux-nvidia-6.11no fix listedUBUNTU-CVE-2026-31575
Ubuntu:24.04:LTSlinux-nvidia-6.17no fix listedUBUNTU-CVE-2026-31575
Ubuntu:22.04:LTSlinux-nvidia-6.2no fix listedUBUNTU-CVE-2026-31575
Ubuntu:22.04:LTSlinux-nvidia-6.5no fix listedUBUNTU-CVE-2026-31575
Ubuntu:22.04:LTSlinux-nvidia-6.86.8.0-1059.62~22.04.1UBUNTU-CVE-2026-31575
Ubuntu:24.04:LTSlinux-nvidia-lowlatency6.8.0-1059.62.1UBUNTU-CVE-2026-31575
Ubuntu:24.04:LTSlinux-nvidia-tegra6.8.0-1030.31UBUNTU-CVE-2026-31575
Ubuntu:22.04:LTSlinux-oem-5.17no fix listedUBUNTU-CVE-2026-31575
Ubuntu:22.04:LTSlinux-oem-6.0no fix listedUBUNTU-CVE-2026-31575
Ubuntu:22.04:LTSlinux-oem-6.1no fix listedUBUNTU-CVE-2026-31575
Ubuntu:24.04:LTSlinux-oem-6.11no fix listedUBUNTU-CVE-2026-31575
Ubuntu:24.04:LTSlinux-oem-6.14no fix listedUBUNTU-CVE-2026-31575
Ubuntu:24.04:LTSlinux-oem-6.17no fix listedUBUNTU-CVE-2026-31575
Ubuntu:22.04:LTSlinux-oem-6.5no fix listedUBUNTU-CVE-2026-31575
Ubuntu:24.04:LTSlinux-oem-6.8no fix listedUBUNTU-CVE-2026-31575
Ubuntu:24.04:LTSlinux-oracle6.8.0-1058.61UBUNTU-CVE-2026-31575
Ubuntu:25.10linux-oracleno fix listedUBUNTU-CVE-2026-31575
Ubuntu:26.04:LTSlinux-oracle7.0.0-1007.7UBUNTU-CVE-2026-31575
Ubuntu:26.04:LTSlinux-oracle7.0.0-1007.7USN-8488-1
Ubuntu:24.04:LTSlinux-oracle-6.14no fix listedUBUNTU-CVE-2026-31575
Ubuntu:24.04:LTSlinux-oracle-6.17no fix listedUBUNTU-CVE-2026-31575
Ubuntu:22.04:LTSlinux-oracle-6.5no fix listedUBUNTU-CVE-2026-31575
Ubuntu:22.04:LTSlinux-oracle-6.86.8.0-1058.61~22.04.1UBUNTU-CVE-2026-31575
Ubuntu:24.04:LTSlinux-raspi6.8.0-1061.65UBUNTU-CVE-2026-31575
Ubuntu:25.10linux-raspino fix listedUBUNTU-CVE-2026-31575
Ubuntu:26.04:LTSlinux-raspi7.0.0-1014.14UBUNTU-CVE-2026-31575
Ubuntu:26.04:LTSlinux-raspi7.0.0-1014.14USN-8488-2
Ubuntu:24.04:LTSlinux-raspi-realtimeno fix listedUBUNTU-CVE-2026-31575
Ubuntu:22.04:LTSlinux-realtimeno fix listedUBUNTU-CVE-2026-31575
Ubuntu:24.04:LTSlinux-realtimeno fix listedUBUNTU-CVE-2026-31575
Ubuntu:25.10linux-realtimeno fix listedUBUNTU-CVE-2026-31575
Ubuntu:26.04:LTSlinux-realtime7.0.0-27.27.1USN-8488-1
Ubuntu:26.04:LTSlinux-realtime7.0.0-27.27.1UBUNTU-CVE-2026-31575
Ubuntu:22.04:LTSlinux-riscvno fix listedUBUNTU-CVE-2026-31575
Ubuntu:24.04:LTSlinux-riscvno fix listedUBUNTU-CVE-2026-31575
Ubuntu:25.10linux-riscvno fix listedUBUNTU-CVE-2026-31575
Ubuntu:26.04:LTSlinux-riscv7.0.0-27.27.1UBUNTU-CVE-2026-31575
Ubuntu:22.04:LTSlinux-riscv-5.19no fix listedUBUNTU-CVE-2026-31575
Ubuntu:24.04:LTSlinux-riscv-6.14no fix listedUBUNTU-CVE-2026-31575
Ubuntu:24.04:LTSlinux-riscv-6.17no fix listedUBUNTU-CVE-2026-31575
Ubuntu:22.04:LTSlinux-riscv-6.5no fix listedUBUNTU-CVE-2026-31575
Ubuntu:22.04:LTSlinux-riscv-6.86.8.0-136.136~22.04.3UBUNTU-CVE-2026-31575
Ubuntu:22.04:LTSlinux-starfive-5.19no fix listedUBUNTU-CVE-2026-31575
Ubuntu:22.04:LTSlinux-starfive-6.2no fix listedUBUNTU-CVE-2026-31575
Ubuntu:22.04:LTSlinux-starfive-6.5no fix listedUBUNTU-CVE-2026-31575
Ubuntu:24.04:LTSlinux-vmware6.8.0-1008.8UBUNTU-CVE-2026-31575
Ubuntu:24.04:LTSlinux-xilinx6.8.0-1033.34UBUNTU-CVE-2026-31575

Affected products (as reported)

VendorProductVersions
Linux Linux a08c7193e4f18dc8508f2d07d0de2c5b94cb39a3 – before 5a525c43baaba0bf3063f86996ca3623b71e4172a08c7193e4f18dc8508f2d07d0de2c5b94cb39a3 – before 574501ede47ac439afd67ba9812bc66722d500baa08c7193e4f18dc8508f2d07d0de2c5b94cb39a3 – before 08282b1bf74c69fc8ecd25493e7fdb5460f01290a08c7193e4f18dc8508f2d07d0de2c5b94cb39a3 – before f4689fc089765d36c026063fb22d23533e883eb6a08c7193e4f18dc8508f2d07d0de2c5b94cb39a3 – before 0217c7fb4de4a40cee667eb21901f3204effe5ac
Linux Linux 6.7

References