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Vulnerability · Published May 28, 2026 · Assigned by Linux

CVE-2026-46159btrfs: fix btrfs_ioctl_space_info() slot_count TOCTOU which can lead to info-leak

Medium 4.7

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 1% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS NVD)4.7Medium
Exploit odds (30 days)<0.1%top 99.2% of all CVEs
Exploited in the wildNo reportsnot in CISA KEV
Attack toolingNoneno public tooling known

Official description

In the Linux kernel, the following vulnerability has been resolved: btrfs: fix btrfs_ioctl_space_info() slot_count TOCTOU which can lead to info-leak btrfs_ioctl_space_info() has a TOCTOU race between two passes over the block group RAID type lists. The first pass counts entries to determine the allocation size, then the second pass fills the buffer. The groups_sem rwlock is released between passes, allowing concurrent block group removal to reduce the entry count. When the second pass fills fewer entries than the first pass counted, copy_to_user() copies the full alloc_size bytes including trailing uninitialized kmalloc bytes to userspace. Fix by copying only total_spaces entries (the actually-filled count from the second pass) instead of alloc_size bytes, and switch to kzalloc so any future copy size mismatch cannot leak heap data.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:12linux6.1.176-1DEBIAN-CVE-2026-46159
Debian:13linux6.12.90-1DEBIAN-CVE-2026-46159
Debian:14linux7.0.7-1DEBIAN-CVE-2026-46159
Ubuntu:22.04:LTSlinux5.15.0-198.208UBUNTU-CVE-2026-46159
Ubuntu:22.04:LTSlinux5.15.0-198.208USN-8875-1
Ubuntu:24.04:LTSlinux6.8.0-136.136UBUNTU-CVE-2026-46159
Ubuntu:25.10linuxno fix listedUBUNTU-CVE-2026-46159
Ubuntu:26.04:LTSlinux7.0.0-28.28UBUNTU-CVE-2026-46159
Ubuntu:22.04:LTSlinux-allwinner-5.19no fix listedUBUNTU-CVE-2026-46159
Ubuntu:22.04:LTSlinux-aws5.15.0-1117.124USN-8875-1
Ubuntu:22.04:LTSlinux-aws5.15.0-1117.124UBUNTU-CVE-2026-46159
Ubuntu:24.04:LTSlinux-aws6.8.0-1061.64UBUNTU-CVE-2026-46159
Ubuntu:25.10linux-awsno fix listedUBUNTU-CVE-2026-46159
Ubuntu:26.04:LTSlinux-aws7.0.0-1009.9UBUNTU-CVE-2026-46159
Ubuntu:22.04:LTSlinux-aws-5.19no fix listedUBUNTU-CVE-2026-46159
Ubuntu:24.04:LTSlinux-aws-6.14no fix listedUBUNTU-CVE-2026-46159
Ubuntu:24.04:LTSlinux-aws-6.17no fix listedUBUNTU-CVE-2026-46159
Ubuntu:22.04:LTSlinux-aws-6.2no fix listedUBUNTU-CVE-2026-46159
Ubuntu:22.04:LTSlinux-aws-6.5no fix listedUBUNTU-CVE-2026-46159
Ubuntu:22.04:LTSlinux-aws-6.86.8.0-1061.64~22.04.1UBUNTU-CVE-2026-46159
Ubuntu:22.04:LTSlinux-azure5.15.0-1123.132UBUNTU-CVE-2026-46159
Ubuntu:22.04:LTSlinux-azure5.15.0-1123.132USN-8875-1
Ubuntu:24.04:LTSlinux-azure6.8.0-1063.71UBUNTU-CVE-2026-46159
Ubuntu:25.10linux-azureno fix listedUBUNTU-CVE-2026-46159
Ubuntu:26.04:LTSlinux-azure7.0.0-1010.10UBUNTU-CVE-2026-46159
Ubuntu:22.04:LTSlinux-azure-5.19no fix listedUBUNTU-CVE-2026-46159
Ubuntu:24.04:LTSlinux-azure-6.11no fix listedUBUNTU-CVE-2026-46159
Ubuntu:24.04:LTSlinux-azure-6.14no fix listedUBUNTU-CVE-2026-46159
Ubuntu:24.04:LTSlinux-azure-6.17no fix listedUBUNTU-CVE-2026-46159
Ubuntu:22.04:LTSlinux-azure-6.2no fix listedUBUNTU-CVE-2026-46159
Ubuntu:22.04:LTSlinux-azure-6.5no fix listedUBUNTU-CVE-2026-46159
Ubuntu:22.04:LTSlinux-azure-6.86.8.0-1063.71~22.04.1UBUNTU-CVE-2026-46159
Ubuntu:24.04:LTSlinux-azure-7.07.0.0-1014.14~24.04.1UBUNTU-CVE-2026-46159
Ubuntu:22.04:LTSlinux-azure-fde5.15.0-1122.131USN-8876-1
Ubuntu:22.04:LTSlinux-azure-fde5.15.0-1122.131UBUNTU-CVE-2026-46159
Ubuntu:24.04:LTSlinux-azure-fde6.8.0-1062.69UBUNTU-CVE-2026-46159
Ubuntu:25.10linux-azure-fdeno fix listedUBUNTU-CVE-2026-46159
Ubuntu:26.04:LTSlinux-azure-fde7.0.0-1009.9UBUNTU-CVE-2026-46159
Ubuntu:22.04:LTSlinux-azure-fde-5.19no fix listedUBUNTU-CVE-2026-46159
Ubuntu:24.04:LTSlinux-azure-fde-6.14no fix listedUBUNTU-CVE-2026-46159
Ubuntu:22.04:LTSlinux-azure-fde-6.2no fix listedUBUNTU-CVE-2026-46159
Ubuntu:22.04:LTSlinux-azure-fde-6.86.8.0-1062.69~22.04.1UBUNTU-CVE-2026-46159
Ubuntu:24.04:LTSlinux-azure-fde-7.07.0.0-1013.13~24.04.1UBUNTU-CVE-2026-46159
Ubuntu:24.04:LTSlinux-azure-nvidiano fix listedUBUNTU-CVE-2026-46159
Ubuntu:24.04:LTSlinux-azure-nvidia-6.14no fix listedUBUNTU-CVE-2026-46159
Ubuntu:22.04:LTSlinux-gcp5.15.0-1118.128USN-8877-1
Ubuntu:22.04:LTSlinux-gcp5.15.0-1118.128UBUNTU-CVE-2026-46159
Ubuntu:24.04:LTSlinux-gcp6.8.0-1064.72UBUNTU-CVE-2026-46159
Ubuntu:25.10linux-gcpno fix listedUBUNTU-CVE-2026-46159
Ubuntu:26.04:LTSlinux-gcp7.0.0-1008.8UBUNTU-CVE-2026-46159
Ubuntu:22.04:LTSlinux-gcp-5.19no fix listedUBUNTU-CVE-2026-46159
Ubuntu:24.04:LTSlinux-gcp-6.11no fix listedUBUNTU-CVE-2026-46159
Ubuntu:24.04:LTSlinux-gcp-6.14no fix listedUBUNTU-CVE-2026-46159
Ubuntu:24.04:LTSlinux-gcp-6.17no fix listedUBUNTU-CVE-2026-46159
Ubuntu:22.04:LTSlinux-gcp-6.2no fix listedUBUNTU-CVE-2026-46159
Ubuntu:22.04:LTSlinux-gcp-6.5no fix listedUBUNTU-CVE-2026-46159
Ubuntu:22.04:LTSlinux-gcp-6.86.8.0-1064.72~22.04.1UBUNTU-CVE-2026-46159
Ubuntu:24.04:LTSlinux-gcp-7.07.0.0-1011.11~24.04.1UBUNTU-CVE-2026-46159
Ubuntu:22.04:LTSlinux-gke5.15.0-1113.119UBUNTU-CVE-2026-46159
Ubuntu:22.04:LTSlinux-gke5.15.0-1113.119USN-8875-1
Ubuntu:24.04:LTSlinux-gke6.8.0-1059.67UBUNTU-CVE-2026-46159
Ubuntu:26.04:LTSlinux-gke7.0.0-1003.4UBUNTU-CVE-2026-46159
Ubuntu:22.04:LTSlinux-gkeop5.15.0-1100.108UBUNTU-CVE-2026-46159
Ubuntu:22.04:LTSlinux-gkeop5.15.0-1100.108USN-8875-1
Ubuntu:24.04:LTSlinux-gkeop6.8.0-1046.50UBUNTU-CVE-2026-46159
Ubuntu:22.04:LTSlinux-hwe-5.19no fix listedUBUNTU-CVE-2026-46159
Ubuntu:24.04:LTSlinux-hwe-6.11no fix listedUBUNTU-CVE-2026-46159
Ubuntu:24.04:LTSlinux-hwe-6.14no fix listedUBUNTU-CVE-2026-46159
Ubuntu:24.04:LTSlinux-hwe-6.17no fix listedUBUNTU-CVE-2026-46159
Ubuntu:22.04:LTSlinux-hwe-6.2no fix listedUBUNTU-CVE-2026-46159
Ubuntu:22.04:LTSlinux-hwe-6.5no fix listedUBUNTU-CVE-2026-46159
Ubuntu:22.04:LTSlinux-hwe-6.86.8.0-136.136~22.04.1UBUNTU-CVE-2026-46159
Ubuntu:24.04:LTSlinux-hwe-7.07.0.0-28.28~24.04.1UBUNTU-CVE-2026-46159
Ubuntu:22.04:LTSlinux-ibm5.15.0-1111.115UBUNTU-CVE-2026-46159
Ubuntu:22.04:LTSlinux-ibm5.15.0-1111.115USN-8875-1
Ubuntu:24.04:LTSlinux-ibm6.8.0-1061.62UBUNTU-CVE-2026-46159
Ubuntu:26.04:LTSlinux-ibm7.0.0-1010.10UBUNTU-CVE-2026-46159
Ubuntu:22.04:LTSlinux-ibm-6.86.8.0-1061.62~22.04.1UBUNTU-CVE-2026-46159
Ubuntu:22.04:LTSlinux-intel-iot-realtimeno fix listedUBUNTU-CVE-2026-46159
Ubuntu:22.04:LTSlinux-intel-iotg5.15.0-1112.118UBUNTU-CVE-2026-46159
Ubuntu:22.04:LTSlinux-intel-iotg5.15.0-1112.118USN-8875-1
Ubuntu:22.04:LTSlinux-kvm5.15.0-1109.114UBUNTU-CVE-2026-46159
Ubuntu:22.04:LTSlinux-kvm5.15.0-1109.114USN-8875-1
Ubuntu:22.04:LTSlinux-lowlatency5.15.0-195.205USN-8875-1
Ubuntu:22.04:LTSlinux-lowlatency5.15.0-195.205UBUNTU-CVE-2026-46159
Ubuntu:24.04:LTSlinux-lowlatency6.8.0-136.136.2UBUNTU-CVE-2026-46159
Ubuntu:22.04:LTSlinux-lowlatency-hwe-5.19no fix listedUBUNTU-CVE-2026-46159
Ubuntu:24.04:LTSlinux-lowlatency-hwe-6.11no fix listedUBUNTU-CVE-2026-46159
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.2no fix listedUBUNTU-CVE-2026-46159
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.5no fix listedUBUNTU-CVE-2026-46159
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.86.8.0-136.136.2~22.04.1UBUNTU-CVE-2026-46159
Ubuntu:22.04:LTSlinux-nvidia5.15.0-1112.113USN-8875-2
Ubuntu:22.04:LTSlinux-nvidia5.15.0-1112.113UBUNTU-CVE-2026-46159
Ubuntu:24.04:LTSlinux-nvidia6.8.0-1059.62UBUNTU-CVE-2026-46159
Ubuntu:26.04:LTSlinux-nvidia7.0.0-1016.16UBUNTU-CVE-2026-46159
Ubuntu:24.04:LTSlinux-nvidia-6.11no fix listedUBUNTU-CVE-2026-46159
Ubuntu:24.04:LTSlinux-nvidia-6.17no fix listedUBUNTU-CVE-2026-46159
Ubuntu:22.04:LTSlinux-nvidia-6.2no fix listedUBUNTU-CVE-2026-46159
Ubuntu:22.04:LTSlinux-nvidia-6.5no fix listedUBUNTU-CVE-2026-46159
Ubuntu:22.04:LTSlinux-nvidia-6.86.8.0-1059.62~22.04.1UBUNTU-CVE-2026-46159
Ubuntu:24.04:LTSlinux-nvidia-7.07.0.0-1016.16~24.04.1UBUNTU-CVE-2026-46159
Ubuntu:26.04:LTSlinux-nvidia-bos7.0.0-2016.16UBUNTU-CVE-2026-46159
Ubuntu:24.04:LTSlinux-nvidia-lowlatency6.8.0-1059.62.1UBUNTU-CVE-2026-46159
Ubuntu:22.04:LTSlinux-nvidia-tegra5.15.0-1070.72UBUNTU-CVE-2026-46159
Ubuntu:24.04:LTSlinux-nvidia-tegra6.8.0-1030.31UBUNTU-CVE-2026-46159
Ubuntu:22.04:LTSlinux-nvidia-tegra-igx5.15.0-1059.59UBUNTU-CVE-2026-46159
Ubuntu:22.04:LTSlinux-oem-5.17no fix listedUBUNTU-CVE-2026-46159
Ubuntu:22.04:LTSlinux-oem-6.0no fix listedUBUNTU-CVE-2026-46159
Ubuntu:22.04:LTSlinux-oem-6.1no fix listedUBUNTU-CVE-2026-46159
Ubuntu:24.04:LTSlinux-oem-6.11no fix listedUBUNTU-CVE-2026-46159
Ubuntu:24.04:LTSlinux-oem-6.14no fix listedUBUNTU-CVE-2026-46159
Ubuntu:24.04:LTSlinux-oem-6.17no fix listedUBUNTU-CVE-2026-46159
Ubuntu:22.04:LTSlinux-oem-6.5no fix listedUBUNTU-CVE-2026-46159
Ubuntu:24.04:LTSlinux-oem-6.8no fix listedUBUNTU-CVE-2026-46159
Ubuntu:26.04:LTSlinux-oem-7.07.0.0-1009.9UBUNTU-CVE-2026-46159
Ubuntu:22.04:LTSlinux-oracle5.15.0-1114.120UBUNTU-CVE-2026-46159
Ubuntu:22.04:LTSlinux-oracle5.15.0-1114.120USN-8875-1
Ubuntu:24.04:LTSlinux-oracle6.8.0-1058.61UBUNTU-CVE-2026-46159
Ubuntu:25.10linux-oracleno fix listedUBUNTU-CVE-2026-46159
Ubuntu:26.04:LTSlinux-oracle7.0.0-1008.8UBUNTU-CVE-2026-46159
Ubuntu:24.04:LTSlinux-oracle-6.14no fix listedUBUNTU-CVE-2026-46159
Ubuntu:24.04:LTSlinux-oracle-6.17no fix listedUBUNTU-CVE-2026-46159
Ubuntu:22.04:LTSlinux-oracle-6.5no fix listedUBUNTU-CVE-2026-46159
Ubuntu:22.04:LTSlinux-oracle-6.86.8.0-1058.61~22.04.1UBUNTU-CVE-2026-46159
Ubuntu:24.04:LTSlinux-oracle-7.07.0.0-1011.11~24.04.1UBUNTU-CVE-2026-46159
Ubuntu:22.04:LTSlinux-raspino fix listedUBUNTU-CVE-2026-46159
Ubuntu:24.04:LTSlinux-raspi6.8.0-1061.65UBUNTU-CVE-2026-46159
Ubuntu:25.10linux-raspino fix listedUBUNTU-CVE-2026-46159
Ubuntu:26.04:LTSlinux-raspi7.0.0-1015.15UBUNTU-CVE-2026-46159
Ubuntu:24.04:LTSlinux-raspi-realtimeno fix listedUBUNTU-CVE-2026-46159
Ubuntu:22.04:LTSlinux-realtimeno fix listedUBUNTU-CVE-2026-46159
Ubuntu:24.04:LTSlinux-realtimeno fix listedUBUNTU-CVE-2026-46159
Ubuntu:25.10linux-realtimeno fix listedUBUNTU-CVE-2026-46159
Ubuntu:26.04:LTSlinux-realtime7.0.0-28.28.1UBUNTU-CVE-2026-46159
Ubuntu:22.04:LTSlinux-riscvno fix listedUBUNTU-CVE-2026-46159
Ubuntu:24.04:LTSlinux-riscvno fix listedUBUNTU-CVE-2026-46159
Ubuntu:25.10linux-riscvno fix listedUBUNTU-CVE-2026-46159
Ubuntu:26.04:LTSlinux-riscv7.0.0-28.28.1UBUNTU-CVE-2026-46159
Ubuntu:22.04:LTSlinux-riscv-5.19no fix listedUBUNTU-CVE-2026-46159
Ubuntu:24.04:LTSlinux-riscv-6.14no fix listedUBUNTU-CVE-2026-46159
Ubuntu:24.04:LTSlinux-riscv-6.17no fix listedUBUNTU-CVE-2026-46159
Ubuntu:22.04:LTSlinux-riscv-6.5no fix listedUBUNTU-CVE-2026-46159
Ubuntu:22.04:LTSlinux-riscv-6.86.8.0-136.136~22.04.3UBUNTU-CVE-2026-46159
Ubuntu:24.04:LTSlinux-riscv-7.07.0.0-28.28.1~24.04.3UBUNTU-CVE-2026-46159
Ubuntu:22.04:LTSlinux-starfive-5.19no fix listedUBUNTU-CVE-2026-46159
Ubuntu:22.04:LTSlinux-starfive-6.2no fix listedUBUNTU-CVE-2026-46159
Ubuntu:22.04:LTSlinux-starfive-6.5no fix listedUBUNTU-CVE-2026-46159
Ubuntu:24.04:LTSlinux-vmware6.8.0-1008.8UBUNTU-CVE-2026-46159
Ubuntu:24.04:LTSlinux-xilinx6.8.0-1033.34UBUNTU-CVE-2026-46159
Ubuntu:22.04:LTSlinux-xilinx-zynqmp5.15.0-1080.84USN-8875-1
Ubuntu:22.04:LTSlinux-xilinx-zynqmp5.15.0-1080.84UBUNTU-CVE-2026-46159

Affected products (as reported)

VendorProductVersions
Linux Linux 7fde62bffb576d384ea49a3aed3403d5609ee5bc – before f407aad350bdea4db300c47433573b7a41630d337fde62bffb576d384ea49a3aed3403d5609ee5bc – before d8224b1be6627c6c3b204bfb264508d27c65ac447fde62bffb576d384ea49a3aed3403d5609ee5bc – before d69a4a6813fdba7c4cc3695a7e843842b240790d7fde62bffb576d384ea49a3aed3403d5609ee5bc – before f5ee467b56764964027c361641f64953fc0f8f9a7fde62bffb576d384ea49a3aed3403d5609ee5bc – before 4fdc6ee0802121d9cd96b8d085e589f51e5a4ec37fde62bffb576d384ea49a3aed3403d5609ee5bc – before 5d12e0ab009ade48c1bff9324fd9bea2c773d0887fde62bffb576d384ea49a3aed3403d5609ee5bc – before d09d67d5de577cedae3de9497dff217e0ac8b6417fde62bffb576d384ea49a3aed3403d5609ee5bc – before 973e57c726c1f8e77259d1c8e519519f1e9aea77
Linux Linux 2.6.34

References