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Vulnerability · Published Dec 8, 2025 · Assigned by Linux

CVE-2025-40307exfat: validate cluster allocation bits of the allocation bitmap

High 7.8

In plain English

A high-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 4% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)7.8High
Exploit odds (30 days)0.1%top 96.1% 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: exfat: validate cluster allocation bits of the allocation bitmap syzbot created an exfat image with cluster bits not set for the allocation bitmap. exfat-fs reads and uses the allocation bitmap without checking this. The problem is that if the start cluster of the allocation bitmap is 6, cluster 6 can be allocated when creating a directory with mkdir. exfat zeros out this cluster in exfat_mkdir, which can delete existing entries. This can reallocate the allocated entries. In addition, the allocation bitmap is also zeroed out, so cluster 6 can be reallocated. This patch adds exfat_test_bitmap_range to validate that clusters used for the allocation bitmap are correctly marked as in-use.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:12linux6.1.187-1DEBIAN-CVE-2025-40307
Debian:13linux6.12.63-1DEBIAN-CVE-2025-40307
Debian:14linux6.17.8-1DEBIAN-CVE-2025-40307
Ubuntu:22.04:LTSlinuxno fix listedUBUNTU-CVE-2025-40307
Ubuntu:24.04:LTSlinux6.8.0-106.106UBUNTU-CVE-2025-40307
Ubuntu:25.10linux6.17.0-14.14UBUNTU-CVE-2025-40307
Ubuntu:22.04:LTSlinux-allwinner-5.19no fix listedUBUNTU-CVE-2025-40307
Ubuntu:22.04:LTSlinux-awsno fix listedUBUNTU-CVE-2025-40307
Ubuntu:24.04:LTSlinux-aws6.8.0-1050.53UBUNTU-CVE-2025-40307
Ubuntu:25.10linux-aws6.17.0-1007.7UBUNTU-CVE-2025-40307
Ubuntu:22.04:LTSlinux-aws-5.19no fix listedUBUNTU-CVE-2025-40307
Ubuntu:24.04:LTSlinux-aws-6.14no fix listedUBUNTU-CVE-2025-40307
Ubuntu:24.04:LTSlinux-aws-6.176.17.0-1007.7~24.04.1UBUNTU-CVE-2025-40307
Ubuntu:22.04:LTSlinux-aws-6.2no fix listedUBUNTU-CVE-2025-40307
Ubuntu:22.04:LTSlinux-aws-6.5no fix listedUBUNTU-CVE-2025-40307
Ubuntu:22.04:LTSlinux-aws-6.86.8.0-1050.53~22.04.1UBUNTU-CVE-2025-40307
Ubuntu:22.04:LTSlinux-azureno fix listedUBUNTU-CVE-2025-40307
Ubuntu:24.04:LTSlinux-azure6.8.0-1051.57UBUNTU-CVE-2025-40307
Ubuntu:25.10linux-azure6.17.0-1008.8UBUNTU-CVE-2025-40307
Ubuntu:22.04:LTSlinux-azure-5.19no fix listedUBUNTU-CVE-2025-40307
Ubuntu:24.04:LTSlinux-azure-6.11no fix listedUBUNTU-CVE-2025-40307
Ubuntu:24.04:LTSlinux-azure-6.14no fix listedUBUNTU-CVE-2025-40307
Ubuntu:22.04:LTSlinux-azure-6.2no fix listedUBUNTU-CVE-2025-40307
Ubuntu:22.04:LTSlinux-azure-6.5no fix listedUBUNTU-CVE-2025-40307
Ubuntu:22.04:LTSlinux-azure-6.86.8.0-1051.57~22.04.1UBUNTU-CVE-2025-40307
Ubuntu:22.04:LTSlinux-azure-fdeno fix listedUBUNTU-CVE-2025-40307
Ubuntu:24.04:LTSlinux-azure-fde6.8.0-1058.65UBUNTU-CVE-2025-40307
Ubuntu:25.10linux-azure-fdeno fix listedUBUNTU-CVE-2025-40307
Ubuntu:22.04:LTSlinux-azure-fde-5.19no fix listedUBUNTU-CVE-2025-40307
Ubuntu:24.04:LTSlinux-azure-fde-6.14no fix listedUBUNTU-CVE-2025-40307
Ubuntu:22.04:LTSlinux-azure-fde-6.2no fix listedUBUNTU-CVE-2025-40307
Ubuntu:22.04:LTSlinux-azure-fde-6.86.8.0-1058.65~22.04.1UBUNTU-CVE-2025-40307
Ubuntu:24.04:LTSlinux-azure-nvidiano fix listedUBUNTU-CVE-2025-40307
Ubuntu:24.04:LTSlinux-azure-nvidia-6.14no fix listedUBUNTU-CVE-2025-40307
Ubuntu:22.04:LTSlinux-gcpno fix listedUBUNTU-CVE-2025-40307
Ubuntu:24.04:LTSlinux-gcp6.8.0-1052.55UBUNTU-CVE-2025-40307
Ubuntu:25.10linux-gcp6.17.0-1007.7UBUNTU-CVE-2025-40307
Ubuntu:22.04:LTSlinux-gcp-5.19no fix listedUBUNTU-CVE-2025-40307
Ubuntu:24.04:LTSlinux-gcp-6.11no fix listedUBUNTU-CVE-2025-40307
Ubuntu:24.04:LTSlinux-gcp-6.14no fix listedUBUNTU-CVE-2025-40307
Ubuntu:24.04:LTSlinux-gcp-6.176.17.0-1008.8~24.04.1UBUNTU-CVE-2025-40307
Ubuntu:22.04:LTSlinux-gcp-6.2no fix listedUBUNTU-CVE-2025-40307
Ubuntu:22.04:LTSlinux-gcp-6.5no fix listedUBUNTU-CVE-2025-40307
Ubuntu:22.04:LTSlinux-gcp-6.86.8.0-1052.55~22.04.1UBUNTU-CVE-2025-40307
Ubuntu:22.04:LTSlinux-gkeno fix listedUBUNTU-CVE-2025-40307
Ubuntu:24.04:LTSlinux-gke6.8.0-1048.53UBUNTU-CVE-2025-40307
Ubuntu:22.04:LTSlinux-gkeopno fix listedUBUNTU-CVE-2025-40307
Ubuntu:24.04:LTSlinux-gkeop6.8.0-1035.38UBUNTU-CVE-2025-40307
Ubuntu:22.04:LTSlinux-hwe-5.19no fix listedUBUNTU-CVE-2025-40307
Ubuntu:24.04:LTSlinux-hwe-6.11no fix listedUBUNTU-CVE-2025-40307
Ubuntu:24.04:LTSlinux-hwe-6.14no fix listedUBUNTU-CVE-2025-40307
Ubuntu:22.04:LTSlinux-hwe-6.2no fix listedUBUNTU-CVE-2025-40307
Ubuntu:22.04:LTSlinux-hwe-6.5no fix listedUBUNTU-CVE-2025-40307
Ubuntu:22.04:LTSlinux-hwe-6.86.8.0-106.106~22.04.1UBUNTU-CVE-2025-40307
Ubuntu:22.04:LTSlinux-ibmno fix listedUBUNTU-CVE-2025-40307
Ubuntu:24.04:LTSlinux-ibm6.8.0-1049.49UBUNTU-CVE-2025-40307
Ubuntu:22.04:LTSlinux-ibm-6.86.8.0-1049.49~22.04.1UBUNTU-CVE-2025-40307
Ubuntu:22.04:LTSlinux-intel-iot-realtimeno fix listedUBUNTU-CVE-2025-40307
Ubuntu:22.04:LTSlinux-intel-iotgno fix listedUBUNTU-CVE-2025-40307
Ubuntu:22.04:LTSlinux-kvmno fix listedUBUNTU-CVE-2025-40307
Ubuntu:22.04:LTSlinux-lowlatencyno fix listedUBUNTU-CVE-2025-40307
Ubuntu:24.04:LTSlinux-lowlatency6.8.0-106.106.1UBUNTU-CVE-2025-40307
Ubuntu:22.04:LTSlinux-lowlatency-hwe-5.19no fix listedUBUNTU-CVE-2025-40307
Ubuntu:24.04:LTSlinux-lowlatency-hwe-6.11no fix listedUBUNTU-CVE-2025-40307
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.2no fix listedUBUNTU-CVE-2025-40307
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.5no fix listedUBUNTU-CVE-2025-40307
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.86.8.0-106.106.1~22.04.1UBUNTU-CVE-2025-40307
Ubuntu:22.04:LTSlinux-nvidiano fix listedUBUNTU-CVE-2025-40307
Ubuntu:24.04:LTSlinux-nvidia6.8.0-1049.52UBUNTU-CVE-2025-40307
Ubuntu:24.04:LTSlinux-nvidia-6.11no fix listedUBUNTU-CVE-2025-40307
Ubuntu:24.04:LTSlinux-nvidia-6.176.17.0-1008.8UBUNTU-CVE-2025-40307
Ubuntu:22.04:LTSlinux-nvidia-6.2no fix listedUBUNTU-CVE-2025-40307
Ubuntu:22.04:LTSlinux-nvidia-6.5no fix listedUBUNTU-CVE-2025-40307
Ubuntu:22.04:LTSlinux-nvidia-6.86.8.0-1049.52~22.04.1UBUNTU-CVE-2025-40307
Ubuntu:24.04:LTSlinux-nvidia-lowlatency6.8.0-1049.52.1UBUNTU-CVE-2025-40307
Ubuntu:22.04:LTSlinux-nvidia-tegrano fix listedUBUNTU-CVE-2025-40307
Ubuntu:24.04:LTSlinux-nvidia-tegra6.8.0-1020.20UBUNTU-CVE-2025-40307
Ubuntu:22.04:LTSlinux-nvidia-tegra-igxno fix listedUBUNTU-CVE-2025-40307
Ubuntu:22.04:LTSlinux-oem-5.17no fix listedUBUNTU-CVE-2025-40307
Ubuntu:22.04:LTSlinux-oem-6.0no fix listedUBUNTU-CVE-2025-40307
Ubuntu:22.04:LTSlinux-oem-6.1no fix listedUBUNTU-CVE-2025-40307
Ubuntu:24.04:LTSlinux-oem-6.11no fix listedUBUNTU-CVE-2025-40307
Ubuntu:24.04:LTSlinux-oem-6.14no fix listedUBUNTU-CVE-2025-40307
Ubuntu:24.04:LTSlinux-oem-6.176.17.0-1011.11UBUNTU-CVE-2025-40307
Ubuntu:22.04:LTSlinux-oem-6.5no fix listedUBUNTU-CVE-2025-40307
Ubuntu:24.04:LTSlinux-oem-6.8no fix listedUBUNTU-CVE-2025-40307
Ubuntu:22.04:LTSlinux-oracleno fix listedUBUNTU-CVE-2025-40307
Ubuntu:24.04:LTSlinux-oracle6.8.0-1047.48UBUNTU-CVE-2025-40307
Ubuntu:25.10linux-oracle6.17.0-1007.7UBUNTU-CVE-2025-40307
Ubuntu:24.04:LTSlinux-oracle-6.14no fix listedUBUNTU-CVE-2025-40307
Ubuntu:24.04:LTSlinux-oracle-6.176.17.0-1007.7~24.04.1UBUNTU-CVE-2025-40307
Ubuntu:22.04:LTSlinux-oracle-6.5no fix listedUBUNTU-CVE-2025-40307
Ubuntu:22.04:LTSlinux-oracle-6.86.8.0-1047.48~22.04.1UBUNTU-CVE-2025-40307
Ubuntu:22.04:LTSlinux-raspino fix listedUBUNTU-CVE-2025-40307
Ubuntu:24.04:LTSlinux-raspi6.8.0-1050.54UBUNTU-CVE-2025-40307
Ubuntu:25.10linux-raspi6.17.0-1008.8UBUNTU-CVE-2025-40307
Ubuntu:24.04:LTSlinux-raspi-realtimeno fix listedUBUNTU-CVE-2025-40307
Ubuntu:22.04:LTSlinux-realtimeno fix listedUBUNTU-CVE-2025-40307
Ubuntu:24.04:LTSlinux-realtimeno fix listedUBUNTU-CVE-2025-40307
Ubuntu:25.10linux-realtime6.17.0-1006.7UBUNTU-CVE-2025-40307
Ubuntu:22.04:LTSlinux-riscvno fix listedUBUNTU-CVE-2025-40307
Ubuntu:24.04:LTSlinux-riscvno fix listedUBUNTU-CVE-2025-40307
Ubuntu:25.10linux-riscv6.17.0-14.14.1UBUNTU-CVE-2025-40307
Ubuntu:22.04:LTSlinux-riscv-5.19no fix listedUBUNTU-CVE-2025-40307
Ubuntu:24.04:LTSlinux-riscv-6.14no fix listedUBUNTU-CVE-2025-40307
Ubuntu:22.04:LTSlinux-riscv-6.5no fix listedUBUNTU-CVE-2025-40307
Ubuntu:22.04:LTSlinux-riscv-6.86.8.0-106.106~22.04.1UBUNTU-CVE-2025-40307
Ubuntu:22.04:LTSlinux-starfive-5.19no fix listedUBUNTU-CVE-2025-40307
Ubuntu:22.04:LTSlinux-starfive-6.2no fix listedUBUNTU-CVE-2025-40307
Ubuntu:22.04:LTSlinux-starfive-6.5no fix listedUBUNTU-CVE-2025-40307
Ubuntu:24.04:LTSlinux-xilinx6.8.0-1028.29UBUNTU-CVE-2025-40307
Ubuntu:22.04:LTSlinux-xilinx-zynqmpno fix listedUBUNTU-CVE-2025-40307

Affected products (as reported)

VendorProductVersions
Linux Linux 1acf1a564b6034b5af1e7fb23cb98cb3bb4f6003 – before 87f827d53bd0688597bda63ae95908e2ad39bac01acf1a564b6034b5af1e7fb23cb98cb3bb4f6003 – before 67ce8034dc0278ddd88cad93d4218a945180dddd1acf1a564b6034b5af1e7fb23cb98cb3bb4f6003 – before 6bc58b4c53795ab5fe00648344aa7d9d61175f901acf1a564b6034b5af1e7fb23cb98cb3bb4f6003 – before 13c1d24803d5b0446b3f6f0fdd67e07ac1fdc7bf1acf1a564b6034b5af1e7fb23cb98cb3bb4f6003 – before 79c1587b6cda74deb0c86fc7ba194b92958c793c
Linux Linux 5.7

References