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Vulnerability · Published Dec 9, 2025 · Assigned by Linux

CVE-2025-40328smb: client: fix potential UAF in smb2_close_cached_fid()

High 8.8

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 0.5% (higher than 40% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)8.8High
Exploit odds (30 days)0.5%top 59.9% 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: smb: client: fix potential UAF in smb2_close_cached_fid() find_or_create_cached_dir() could grab a new reference after kref_put() had seen the refcount drop to zero but before cfid_list_lock is acquired in smb2_close_cached_fid(), leading to use-after-free. Switch to kref_put_lock() so cfid_release() is called with cfid_list_lock held, closing that gap.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:12linuxno fix listedDEBIAN-CVE-2025-40328
Debian:13linux6.12.63-1DEBIAN-CVE-2025-40328
Debian:14linux6.17.8-1DEBIAN-CVE-2025-40328
Ubuntu:24.04:LTSlinux6.8.0-106.106UBUNTU-CVE-2025-40328
Ubuntu:25.10linux6.17.0-14.14UBUNTU-CVE-2025-40328
Ubuntu:22.04:LTSlinux-allwinner-5.19no fix listedUBUNTU-CVE-2025-40328
Ubuntu:24.04:LTSlinux-aws6.8.0-1050.53UBUNTU-CVE-2025-40328
Ubuntu:25.10linux-aws6.17.0-1007.7UBUNTU-CVE-2025-40328
Ubuntu:22.04:LTSlinux-aws-5.19no fix listedUBUNTU-CVE-2025-40328
Ubuntu:24.04:LTSlinux-aws-6.14no fix listedUBUNTU-CVE-2025-40328
Ubuntu:24.04:LTSlinux-aws-6.176.17.0-1007.7~24.04.1UBUNTU-CVE-2025-40328
Ubuntu:22.04:LTSlinux-aws-6.2no fix listedUBUNTU-CVE-2025-40328
Ubuntu:22.04:LTSlinux-aws-6.5no fix listedUBUNTU-CVE-2025-40328
Ubuntu:22.04:LTSlinux-aws-6.86.8.0-1050.53~22.04.1UBUNTU-CVE-2025-40328
Ubuntu:22.04:LTSlinux-azureno fix listedUBUNTU-CVE-2025-40328
Ubuntu:24.04:LTSlinux-azure6.8.0-1051.57UBUNTU-CVE-2025-40328
Ubuntu:25.10linux-azure6.17.0-1008.8UBUNTU-CVE-2025-40328
Ubuntu:22.04:LTSlinux-azure-5.19no fix listedUBUNTU-CVE-2025-40328
Ubuntu:24.04:LTSlinux-azure-6.11no fix listedUBUNTU-CVE-2025-40328
Ubuntu:24.04:LTSlinux-azure-6.14no fix listedUBUNTU-CVE-2025-40328
Ubuntu:22.04:LTSlinux-azure-6.2no fix listedUBUNTU-CVE-2025-40328
Ubuntu:22.04:LTSlinux-azure-6.5no fix listedUBUNTU-CVE-2025-40328
Ubuntu:22.04:LTSlinux-azure-6.86.8.0-1051.57~22.04.1UBUNTU-CVE-2025-40328
Ubuntu:22.04:LTSlinux-azure-fdeno fix listedUBUNTU-CVE-2025-40328
Ubuntu:24.04:LTSlinux-azure-fde6.8.0-1058.65UBUNTU-CVE-2025-40328
Ubuntu:25.10linux-azure-fdeno fix listedUBUNTU-CVE-2025-40328
Ubuntu:22.04:LTSlinux-azure-fde-5.19no fix listedUBUNTU-CVE-2025-40328
Ubuntu:24.04:LTSlinux-azure-fde-6.14no fix listedUBUNTU-CVE-2025-40328
Ubuntu:22.04:LTSlinux-azure-fde-6.2no fix listedUBUNTU-CVE-2025-40328
Ubuntu:22.04:LTSlinux-azure-fde-6.86.8.0-1058.65~22.04.1UBUNTU-CVE-2025-40328
Ubuntu:24.04:LTSlinux-azure-nvidiano fix listedUBUNTU-CVE-2025-40328
Ubuntu:24.04:LTSlinux-azure-nvidia-6.14no fix listedUBUNTU-CVE-2025-40328
Ubuntu:24.04:LTSlinux-gcp6.8.0-1052.55UBUNTU-CVE-2025-40328
Ubuntu:25.10linux-gcp6.17.0-1007.7UBUNTU-CVE-2025-40328
Ubuntu:22.04:LTSlinux-gcp-5.19no fix listedUBUNTU-CVE-2025-40328
Ubuntu:24.04:LTSlinux-gcp-6.11no fix listedUBUNTU-CVE-2025-40328
Ubuntu:24.04:LTSlinux-gcp-6.14no fix listedUBUNTU-CVE-2025-40328
Ubuntu:24.04:LTSlinux-gcp-6.176.17.0-1008.8~24.04.1UBUNTU-CVE-2025-40328
Ubuntu:22.04:LTSlinux-gcp-6.2no fix listedUBUNTU-CVE-2025-40328
Ubuntu:22.04:LTSlinux-gcp-6.5no fix listedUBUNTU-CVE-2025-40328
Ubuntu:22.04:LTSlinux-gcp-6.86.8.0-1052.55~22.04.1UBUNTU-CVE-2025-40328
Ubuntu:24.04:LTSlinux-gke6.8.0-1048.53UBUNTU-CVE-2025-40328
Ubuntu:24.04:LTSlinux-gkeop6.8.0-1035.38UBUNTU-CVE-2025-40328
Ubuntu:22.04:LTSlinux-hwe-5.19no fix listedUBUNTU-CVE-2025-40328
Ubuntu:24.04:LTSlinux-hwe-6.11no fix listedUBUNTU-CVE-2025-40328
Ubuntu:24.04:LTSlinux-hwe-6.14no fix listedUBUNTU-CVE-2025-40328
Ubuntu:22.04:LTSlinux-hwe-6.2no fix listedUBUNTU-CVE-2025-40328
Ubuntu:22.04:LTSlinux-hwe-6.5no fix listedUBUNTU-CVE-2025-40328
Ubuntu:22.04:LTSlinux-hwe-6.86.8.0-106.106~22.04.1UBUNTU-CVE-2025-40328
Ubuntu:24.04:LTSlinux-ibm6.8.0-1049.49UBUNTU-CVE-2025-40328
Ubuntu:22.04:LTSlinux-ibm-6.86.8.0-1049.49~22.04.1UBUNTU-CVE-2025-40328
Ubuntu:22.04:LTSlinux-intel-iot-realtimeno fix listedUBUNTU-CVE-2025-40328
Ubuntu:24.04:LTSlinux-lowlatency6.8.0-106.106.1UBUNTU-CVE-2025-40328
Ubuntu:22.04:LTSlinux-lowlatency-hwe-5.19no fix listedUBUNTU-CVE-2025-40328
Ubuntu:24.04:LTSlinux-lowlatency-hwe-6.11no fix listedUBUNTU-CVE-2025-40328
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.2no fix listedUBUNTU-CVE-2025-40328
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.5no fix listedUBUNTU-CVE-2025-40328
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.86.8.0-106.106.1~22.04.1UBUNTU-CVE-2025-40328
Ubuntu:24.04:LTSlinux-nvidia6.8.0-1049.52UBUNTU-CVE-2025-40328
Ubuntu:24.04:LTSlinux-nvidia-6.11no fix listedUBUNTU-CVE-2025-40328
Ubuntu:24.04:LTSlinux-nvidia-6.176.17.0-1008.8UBUNTU-CVE-2025-40328
Ubuntu:22.04:LTSlinux-nvidia-6.2no fix listedUBUNTU-CVE-2025-40328
Ubuntu:22.04:LTSlinux-nvidia-6.5no fix listedUBUNTU-CVE-2025-40328
Ubuntu:22.04:LTSlinux-nvidia-6.86.8.0-1049.52~22.04.1UBUNTU-CVE-2025-40328
Ubuntu:24.04:LTSlinux-nvidia-lowlatency6.8.0-1049.52.1UBUNTU-CVE-2025-40328
Ubuntu:24.04:LTSlinux-nvidia-tegra6.8.0-1020.20UBUNTU-CVE-2025-40328
Ubuntu:22.04:LTSlinux-oem-5.17no fix listedUBUNTU-CVE-2025-40328
Ubuntu:22.04:LTSlinux-oem-6.0no fix listedUBUNTU-CVE-2025-40328
Ubuntu:22.04:LTSlinux-oem-6.1no fix listedUBUNTU-CVE-2025-40328
Ubuntu:24.04:LTSlinux-oem-6.11no fix listedUBUNTU-CVE-2025-40328
Ubuntu:24.04:LTSlinux-oem-6.14no fix listedUBUNTU-CVE-2025-40328
Ubuntu:24.04:LTSlinux-oem-6.176.17.0-1011.11UBUNTU-CVE-2025-40328
Ubuntu:22.04:LTSlinux-oem-6.5no fix listedUBUNTU-CVE-2025-40328
Ubuntu:24.04:LTSlinux-oem-6.8no fix listedUBUNTU-CVE-2025-40328
Ubuntu:24.04:LTSlinux-oracle6.8.0-1047.48UBUNTU-CVE-2025-40328
Ubuntu:25.10linux-oracle6.17.0-1007.7UBUNTU-CVE-2025-40328
Ubuntu:24.04:LTSlinux-oracle-6.14no fix listedUBUNTU-CVE-2025-40328
Ubuntu:24.04:LTSlinux-oracle-6.176.17.0-1007.7~24.04.1UBUNTU-CVE-2025-40328
Ubuntu:22.04:LTSlinux-oracle-6.5no fix listedUBUNTU-CVE-2025-40328
Ubuntu:22.04:LTSlinux-oracle-6.86.8.0-1047.48~22.04.1UBUNTU-CVE-2025-40328
Ubuntu:24.04:LTSlinux-raspi6.8.0-1050.54UBUNTU-CVE-2025-40328
Ubuntu:25.10linux-raspi6.17.0-1008.8UBUNTU-CVE-2025-40328
Ubuntu:24.04:LTSlinux-raspi-realtimeno fix listedUBUNTU-CVE-2025-40328
Ubuntu:22.04:LTSlinux-realtimeno fix listedUBUNTU-CVE-2025-40328
Ubuntu:24.04:LTSlinux-realtimeno fix listedUBUNTU-CVE-2025-40328
Ubuntu:25.10linux-realtime6.17.0-1006.7UBUNTU-CVE-2025-40328
Ubuntu:22.04:LTSlinux-riscvno fix listedUBUNTU-CVE-2025-40328
Ubuntu:24.04:LTSlinux-riscvno fix listedUBUNTU-CVE-2025-40328
Ubuntu:25.10linux-riscv6.17.0-14.14.1UBUNTU-CVE-2025-40328
Ubuntu:22.04:LTSlinux-riscv-5.19no fix listedUBUNTU-CVE-2025-40328
Ubuntu:24.04:LTSlinux-riscv-6.14no fix listedUBUNTU-CVE-2025-40328
Ubuntu:22.04:LTSlinux-riscv-6.5no fix listedUBUNTU-CVE-2025-40328
Ubuntu:22.04:LTSlinux-riscv-6.86.8.0-106.106~22.04.1UBUNTU-CVE-2025-40328
Ubuntu:22.04:LTSlinux-starfive-5.19no fix listedUBUNTU-CVE-2025-40328
Ubuntu:22.04:LTSlinux-starfive-6.2no fix listedUBUNTU-CVE-2025-40328
Ubuntu:22.04:LTSlinux-starfive-6.5no fix listedUBUNTU-CVE-2025-40328
Ubuntu:24.04:LTSlinux-xilinx6.8.0-1028.29UBUNTU-CVE-2025-40328

Affected products (as reported)

VendorProductVersions
Linux Linux ebe98f1447bbccf8228335c62d86af02a0ed23f7 – before bb3355ce9dcaba1b4a766f98b2ad373cab6cd626ebe98f1447bbccf8228335c62d86af02a0ed23f7 – before cb52d9c86d70298de0ab7c7953653898cbc0efd6ebe98f1447bbccf8228335c62d86af02a0ed23f7 – before 065bd62412271a2d734810dd50336cae88c54427ebe98f1447bbccf8228335c62d86af02a0ed23f7 – before bdb596ceb4b7c3f28786a33840263728217fbcf5ebe98f1447bbccf8228335c62d86af02a0ed23f7 – before 734e99623c5b65bf2c03e35978a0b980ebc3c2f8
Linux Linux 6.1

References