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Vulnerability · Published Dec 8, 2025 · Assigned by Linux

CVE-2025-40320smb: client: fix potential cfid UAF in smb2_query_info_compound

Critical 9.8

In plain English

A critical-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 0.4% (higher than 36% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)9.8Critical
Exploit odds (30 days)0.4%top 63.7% 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 cfid UAF in smb2_query_info_compound When smb2_query_info_compound() retries, a previously allocated cfid may have been freed in the first attempt. Because cfid wasn't reset on replay, later cleanup could act on a stale pointer, leading to a potential use-after-free. Reinitialize cfid to NULL under the replay label. Example trace (trimmed): refcount_t: underflow; use-after-free. WARNING: CPU: 1 PID: 11224 at ../lib/refcount.c:28 refcount_warn_saturate+0x9c/0x110 [...] RIP: 0010:refcount_warn_saturate+0x9c/0x110 [...] Call Trace: <TASK> smb2_query_info_compound+0x29c/0x5c0 [cifs f90b72658819bd21c94769b6a652029a07a7172f] ? step_into+0x10d/0x690 ? __legitimize_path+0x28/0x60 smb2_queryfs+0x6a/0xf0 [cifs f90b72658819bd21c94769b6a652029a07a7172f] smb311_queryfs+0x12d/0x140 [cifs f90b72658819bd21c94769b6a652029a07a7172f] ? kmem_cache_alloc+0x18a/0x340 ? getname_flags+0x46/0x1e0 cifs_statfs+0x9f/0x2b0 [cifs f90b72658819bd21c94769b6a652029a07a7172f] statfs_by_dentry+0x67/0x90 vfs_statfs+0x16/0xd0 user_statfs+0x54/0xa0 __do_sys_statfs+0x20/0x50 do_syscall_64+0x58/0x80

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
AlmaLinux:10kernel6.12.0-211.7.1.el10_2ALSA-2026:18134
AlmaLinux:10kernel-64k6.12.0-211.7.1.el10_2ALSA-2026:18134
AlmaLinux:10kernel-64k-core6.12.0-211.7.1.el10_2ALSA-2026:18134
AlmaLinux:10kernel-64k-debug6.12.0-211.7.1.el10_2ALSA-2026:18134
AlmaLinux:10kernel-64k-debug-core6.12.0-211.7.1.el10_2ALSA-2026:18134
AlmaLinux:10kernel-64k-debug-devel6.12.0-211.7.1.el10_2ALSA-2026:18134
AlmaLinux:10kernel-64k-debug-devel-matched6.12.0-211.7.1.el10_2ALSA-2026:18134
AlmaLinux:10kernel-64k-debug-modules6.12.0-211.7.1.el10_2ALSA-2026:18134
AlmaLinux:10kernel-64k-debug-modules-core6.12.0-211.7.1.el10_2ALSA-2026:18134
AlmaLinux:10kernel-64k-debug-modules-extra6.12.0-211.7.1.el10_2ALSA-2026:18134
AlmaLinux:10kernel-64k-devel6.12.0-211.7.1.el10_2ALSA-2026:18134
AlmaLinux:10kernel-64k-devel-matched6.12.0-211.7.1.el10_2ALSA-2026:18134
AlmaLinux:10kernel-64k-modules6.12.0-211.7.1.el10_2ALSA-2026:18134
AlmaLinux:10kernel-64k-modules-core6.12.0-211.7.1.el10_2ALSA-2026:18134
AlmaLinux:10kernel-64k-modules-extra6.12.0-211.7.1.el10_2ALSA-2026:18134
AlmaLinux:10kernel-abi-stablelists6.12.0-211.7.1.el10_2ALSA-2026:18134
AlmaLinux:10kernel-core6.12.0-211.7.1.el10_2ALSA-2026:18134
AlmaLinux:10kernel-cross-headers6.12.0-211.7.1.el10_2ALSA-2026:18134
AlmaLinux:10kernel-debug6.12.0-211.7.1.el10_2ALSA-2026:18134
AlmaLinux:10kernel-debug-core6.12.0-211.7.1.el10_2ALSA-2026:18134
AlmaLinux:10kernel-debug-devel6.12.0-211.7.1.el10_2ALSA-2026:18134
AlmaLinux:10kernel-debug-devel-matched6.12.0-211.7.1.el10_2ALSA-2026:18134
AlmaLinux:10kernel-debug-modules6.12.0-211.7.1.el10_2ALSA-2026:18134
AlmaLinux:10kernel-debug-modules-core6.12.0-211.7.1.el10_2ALSA-2026:18134
AlmaLinux:10kernel-debug-modules-extra6.12.0-211.7.1.el10_2ALSA-2026:18134
AlmaLinux:10kernel-debug-uki-virt6.12.0-211.7.1.el10_2ALSA-2026:18134
AlmaLinux:10kernel-devel6.12.0-211.7.1.el10_2ALSA-2026:18134
AlmaLinux:10kernel-devel-matched6.12.0-211.7.1.el10_2ALSA-2026:18134
AlmaLinux:10kernel-doc6.12.0-211.7.1.el10_2ALSA-2026:18134
AlmaLinux:10kernel-headers6.12.0-211.7.1.el10_2ALSA-2026:18134
AlmaLinux:10kernel-modules6.12.0-211.7.1.el10_2ALSA-2026:18134
AlmaLinux:10kernel-modules-core6.12.0-211.7.1.el10_2ALSA-2026:18134
AlmaLinux:10kernel-modules-extra6.12.0-211.7.1.el10_2ALSA-2026:18134
AlmaLinux:10kernel-modules-extra-matched6.12.0-211.7.1.el10_2ALSA-2026:18134
AlmaLinux:10kernel-rt6.12.0-211.7.1.el10_2ALSA-2026:18134
AlmaLinux:10kernel-rt-64k6.12.0-211.7.1.el10_2ALSA-2026:18134
AlmaLinux:10kernel-rt-64k-core6.12.0-211.7.1.el10_2ALSA-2026:18134
AlmaLinux:10kernel-rt-64k-debug6.12.0-211.7.1.el10_2ALSA-2026:18134
AlmaLinux:10kernel-rt-64k-debug-core6.12.0-211.7.1.el10_2ALSA-2026:18134
AlmaLinux:10kernel-rt-64k-debug-devel6.12.0-211.7.1.el10_2ALSA-2026:18134
AlmaLinux:10kernel-rt-64k-debug-modules6.12.0-211.7.1.el10_2ALSA-2026:18134
AlmaLinux:10kernel-rt-64k-debug-modules-core6.12.0-211.7.1.el10_2ALSA-2026:18134
AlmaLinux:10kernel-rt-64k-debug-modules-extra6.12.0-211.7.1.el10_2ALSA-2026:18134
AlmaLinux:10kernel-rt-64k-devel6.12.0-211.7.1.el10_2ALSA-2026:18134
AlmaLinux:10kernel-rt-64k-modules6.12.0-211.7.1.el10_2ALSA-2026:18134
AlmaLinux:10kernel-rt-64k-modules-core6.12.0-211.7.1.el10_2ALSA-2026:18134
AlmaLinux:10kernel-rt-64k-modules-extra6.12.0-211.7.1.el10_2ALSA-2026:18134
AlmaLinux:10kernel-rt-core6.12.0-211.7.1.el10_2ALSA-2026:18134
AlmaLinux:10kernel-rt-debug6.12.0-211.7.1.el10_2ALSA-2026:18134
AlmaLinux:10kernel-rt-debug-core6.12.0-211.7.1.el10_2ALSA-2026:18134
AlmaLinux:10kernel-rt-debug-devel6.12.0-211.7.1.el10_2ALSA-2026:18134
AlmaLinux:10kernel-rt-debug-modules6.12.0-211.7.1.el10_2ALSA-2026:18134
AlmaLinux:10kernel-rt-debug-modules-core6.12.0-211.7.1.el10_2ALSA-2026:18134
AlmaLinux:10kernel-rt-debug-modules-extra6.12.0-211.7.1.el10_2ALSA-2026:18134
AlmaLinux:10kernel-rt-devel6.12.0-211.7.1.el10_2ALSA-2026:18134
AlmaLinux:10kernel-rt-modules6.12.0-211.7.1.el10_2ALSA-2026:18134
AlmaLinux:10kernel-rt-modules-core6.12.0-211.7.1.el10_2ALSA-2026:18134
AlmaLinux:10kernel-rt-modules-extra6.12.0-211.7.1.el10_2ALSA-2026:18134
AlmaLinux:10kernel-tools6.12.0-211.7.1.el10_2ALSA-2026:18134
AlmaLinux:10kernel-tools-libs6.12.0-211.7.1.el10_2ALSA-2026:18134
AlmaLinux:10kernel-tools-libs-devel6.12.0-211.7.1.el10_2ALSA-2026:18134
AlmaLinux:10kernel-uki-virt6.12.0-211.7.1.el10_2ALSA-2026:18134
AlmaLinux:10kernel-uki-virt-addons6.12.0-211.7.1.el10_2ALSA-2026:18134
AlmaLinux:10kernel-zfcpdump6.12.0-211.7.1.el10_2ALSA-2026:18134
AlmaLinux:10kernel-zfcpdump-core6.12.0-211.7.1.el10_2ALSA-2026:18134
AlmaLinux:10kernel-zfcpdump-devel6.12.0-211.7.1.el10_2ALSA-2026:18134
AlmaLinux:10kernel-zfcpdump-devel-matched6.12.0-211.7.1.el10_2ALSA-2026:18134
AlmaLinux:10kernel-zfcpdump-modules6.12.0-211.7.1.el10_2ALSA-2026:18134
AlmaLinux:10kernel-zfcpdump-modules-core6.12.0-211.7.1.el10_2ALSA-2026:18134
AlmaLinux:10kernel-zfcpdump-modules-extra6.12.0-211.7.1.el10_2ALSA-2026:18134
AlmaLinux:10libperf6.12.0-211.7.1.el10_2ALSA-2026:18134
AlmaLinux:10perf6.12.0-211.7.1.el10_2ALSA-2026:18134
AlmaLinux:10python3-perf6.12.0-211.7.1.el10_2ALSA-2026:18134
AlmaLinux:10rtla6.12.0-211.7.1.el10_2ALSA-2026:18134
AlmaLinux:10rv6.12.0-211.7.1.el10_2ALSA-2026:18134
Debian:13linux6.12.63-1DEBIAN-CVE-2025-40320
Debian:14linux6.17.8-1DEBIAN-CVE-2025-40320
Ubuntu:24.04:LTSlinux6.8.0-106.106UBUNTU-CVE-2025-40320
Ubuntu:25.10linux6.17.0-14.14UBUNTU-CVE-2025-40320
Ubuntu:22.04:LTSlinux-allwinner-5.19no fix listedUBUNTU-CVE-2025-40320
Ubuntu:24.04:LTSlinux-aws6.8.0-1050.53UBUNTU-CVE-2025-40320
Ubuntu:25.10linux-aws6.17.0-1007.7UBUNTU-CVE-2025-40320
Ubuntu:22.04:LTSlinux-aws-5.19no fix listedUBUNTU-CVE-2025-40320
Ubuntu:24.04:LTSlinux-aws-6.14no fix listedUBUNTU-CVE-2025-40320
Ubuntu:24.04:LTSlinux-aws-6.176.17.0-1007.7~24.04.1UBUNTU-CVE-2025-40320
Ubuntu:22.04:LTSlinux-aws-6.2no fix listedUBUNTU-CVE-2025-40320
Ubuntu:22.04:LTSlinux-aws-6.5no fix listedUBUNTU-CVE-2025-40320
Ubuntu:22.04:LTSlinux-aws-6.86.8.0-1050.53~22.04.1UBUNTU-CVE-2025-40320
Ubuntu:24.04:LTSlinux-azure6.8.0-1051.57UBUNTU-CVE-2025-40320
Ubuntu:25.10linux-azure6.17.0-1008.8UBUNTU-CVE-2025-40320
Ubuntu:22.04:LTSlinux-azure-5.19no fix listedUBUNTU-CVE-2025-40320
Ubuntu:24.04:LTSlinux-azure-6.11no fix listedUBUNTU-CVE-2025-40320
Ubuntu:24.04:LTSlinux-azure-6.14no fix listedUBUNTU-CVE-2025-40320
Ubuntu:22.04:LTSlinux-azure-6.2no fix listedUBUNTU-CVE-2025-40320
Ubuntu:22.04:LTSlinux-azure-6.5no fix listedUBUNTU-CVE-2025-40320
Ubuntu:22.04:LTSlinux-azure-6.86.8.0-1051.57~22.04.1UBUNTU-CVE-2025-40320
Ubuntu:24.04:LTSlinux-azure-fde6.8.0-1058.65UBUNTU-CVE-2025-40320
Ubuntu:25.10linux-azure-fdeno fix listedUBUNTU-CVE-2025-40320
Ubuntu:22.04:LTSlinux-azure-fde-5.19no fix listedUBUNTU-CVE-2025-40320
Ubuntu:24.04:LTSlinux-azure-fde-6.14no fix listedUBUNTU-CVE-2025-40320
Ubuntu:22.04:LTSlinux-azure-fde-6.2no fix listedUBUNTU-CVE-2025-40320
Ubuntu:22.04:LTSlinux-azure-fde-6.86.8.0-1058.65~22.04.1UBUNTU-CVE-2025-40320
Ubuntu:24.04:LTSlinux-azure-nvidiano fix listedUBUNTU-CVE-2025-40320
Ubuntu:24.04:LTSlinux-azure-nvidia-6.14no fix listedUBUNTU-CVE-2025-40320
Ubuntu:24.04:LTSlinux-gcp6.8.0-1052.55UBUNTU-CVE-2025-40320
Ubuntu:25.10linux-gcp6.17.0-1007.7UBUNTU-CVE-2025-40320
Ubuntu:22.04:LTSlinux-gcp-5.19no fix listedUBUNTU-CVE-2025-40320
Ubuntu:24.04:LTSlinux-gcp-6.11no fix listedUBUNTU-CVE-2025-40320
Ubuntu:24.04:LTSlinux-gcp-6.14no fix listedUBUNTU-CVE-2025-40320
Ubuntu:24.04:LTSlinux-gcp-6.176.17.0-1008.8~24.04.1UBUNTU-CVE-2025-40320
Ubuntu:22.04:LTSlinux-gcp-6.2no fix listedUBUNTU-CVE-2025-40320
Ubuntu:22.04:LTSlinux-gcp-6.5no fix listedUBUNTU-CVE-2025-40320
Ubuntu:22.04:LTSlinux-gcp-6.86.8.0-1052.55~22.04.1UBUNTU-CVE-2025-40320
Ubuntu:24.04:LTSlinux-gke6.8.0-1048.53UBUNTU-CVE-2025-40320
Ubuntu:24.04:LTSlinux-gkeop6.8.0-1035.38UBUNTU-CVE-2025-40320
Ubuntu:22.04:LTSlinux-hwe-5.19no fix listedUBUNTU-CVE-2025-40320
Ubuntu:24.04:LTSlinux-hwe-6.11no fix listedUBUNTU-CVE-2025-40320
Ubuntu:24.04:LTSlinux-hwe-6.14no fix listedUBUNTU-CVE-2025-40320
Ubuntu:22.04:LTSlinux-hwe-6.2no fix listedUBUNTU-CVE-2025-40320
Ubuntu:22.04:LTSlinux-hwe-6.5no fix listedUBUNTU-CVE-2025-40320
Ubuntu:22.04:LTSlinux-hwe-6.86.8.0-106.106~22.04.1UBUNTU-CVE-2025-40320
Ubuntu:24.04:LTSlinux-ibm6.8.0-1049.49UBUNTU-CVE-2025-40320
Ubuntu:22.04:LTSlinux-ibm-6.86.8.0-1049.49~22.04.1UBUNTU-CVE-2025-40320
Ubuntu:22.04:LTSlinux-intel-iot-realtimeno fix listedUBUNTU-CVE-2025-40320
Ubuntu:24.04:LTSlinux-lowlatency6.8.0-106.106.1UBUNTU-CVE-2025-40320
Ubuntu:22.04:LTSlinux-lowlatency-hwe-5.19no fix listedUBUNTU-CVE-2025-40320
Ubuntu:24.04:LTSlinux-lowlatency-hwe-6.11no fix listedUBUNTU-CVE-2025-40320
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.2no fix listedUBUNTU-CVE-2025-40320
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.5no fix listedUBUNTU-CVE-2025-40320
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.86.8.0-106.106.1~22.04.1UBUNTU-CVE-2025-40320
Ubuntu:24.04:LTSlinux-nvidia6.8.0-1049.52UBUNTU-CVE-2025-40320
Ubuntu:24.04:LTSlinux-nvidia-6.11no fix listedUBUNTU-CVE-2025-40320
Ubuntu:24.04:LTSlinux-nvidia-6.176.17.0-1008.8UBUNTU-CVE-2025-40320
Ubuntu:22.04:LTSlinux-nvidia-6.2no fix listedUBUNTU-CVE-2025-40320
Ubuntu:22.04:LTSlinux-nvidia-6.5no fix listedUBUNTU-CVE-2025-40320
Ubuntu:22.04:LTSlinux-nvidia-6.86.8.0-1049.52~22.04.1UBUNTU-CVE-2025-40320
Ubuntu:24.04:LTSlinux-nvidia-lowlatency6.8.0-1049.52.1UBUNTU-CVE-2025-40320
Ubuntu:24.04:LTSlinux-nvidia-tegra6.8.0-1020.20UBUNTU-CVE-2025-40320
Ubuntu:22.04:LTSlinux-oem-5.17no fix listedUBUNTU-CVE-2025-40320
Ubuntu:22.04:LTSlinux-oem-6.0no fix listedUBUNTU-CVE-2025-40320
Ubuntu:22.04:LTSlinux-oem-6.1no fix listedUBUNTU-CVE-2025-40320
Ubuntu:24.04:LTSlinux-oem-6.11no fix listedUBUNTU-CVE-2025-40320
Ubuntu:24.04:LTSlinux-oem-6.14no fix listedUBUNTU-CVE-2025-40320
Ubuntu:24.04:LTSlinux-oem-6.176.17.0-1011.11UBUNTU-CVE-2025-40320
Ubuntu:22.04:LTSlinux-oem-6.5no fix listedUBUNTU-CVE-2025-40320
Ubuntu:24.04:LTSlinux-oem-6.8no fix listedUBUNTU-CVE-2025-40320
Ubuntu:24.04:LTSlinux-oracle6.8.0-1047.48UBUNTU-CVE-2025-40320
Ubuntu:25.10linux-oracle6.17.0-1007.7UBUNTU-CVE-2025-40320
Ubuntu:24.04:LTSlinux-oracle-6.14no fix listedUBUNTU-CVE-2025-40320
Ubuntu:24.04:LTSlinux-oracle-6.176.17.0-1007.7~24.04.1UBUNTU-CVE-2025-40320
Ubuntu:22.04:LTSlinux-oracle-6.5no fix listedUBUNTU-CVE-2025-40320
Ubuntu:22.04:LTSlinux-oracle-6.86.8.0-1047.48~22.04.1UBUNTU-CVE-2025-40320
Ubuntu:24.04:LTSlinux-raspi6.8.0-1050.54UBUNTU-CVE-2025-40320
Ubuntu:25.10linux-raspi6.17.0-1008.8UBUNTU-CVE-2025-40320
Ubuntu:24.04:LTSlinux-raspi-realtimeno fix listedUBUNTU-CVE-2025-40320
Ubuntu:22.04:LTSlinux-realtimeno fix listedUBUNTU-CVE-2025-40320
Ubuntu:24.04:LTSlinux-realtimeno fix listedUBUNTU-CVE-2025-40320
Ubuntu:25.10linux-realtime6.17.0-1006.7UBUNTU-CVE-2025-40320
Ubuntu:22.04:LTSlinux-riscvno fix listedUBUNTU-CVE-2025-40320
Ubuntu:24.04:LTSlinux-riscvno fix listedUBUNTU-CVE-2025-40320
Ubuntu:25.10linux-riscv6.17.0-14.14.1UBUNTU-CVE-2025-40320
Ubuntu:22.04:LTSlinux-riscv-5.19no fix listedUBUNTU-CVE-2025-40320
Ubuntu:24.04:LTSlinux-riscv-6.14no fix listedUBUNTU-CVE-2025-40320
Ubuntu:22.04:LTSlinux-riscv-6.5no fix listedUBUNTU-CVE-2025-40320
Ubuntu:22.04:LTSlinux-riscv-6.86.8.0-106.106~22.04.1UBUNTU-CVE-2025-40320
Ubuntu:22.04:LTSlinux-starfive-5.19no fix listedUBUNTU-CVE-2025-40320
Ubuntu:22.04:LTSlinux-starfive-6.2no fix listedUBUNTU-CVE-2025-40320
Ubuntu:22.04:LTSlinux-starfive-6.5no fix listedUBUNTU-CVE-2025-40320
Ubuntu:24.04:LTSlinux-xilinx6.8.0-1028.29UBUNTU-CVE-2025-40320

Affected products (as reported)

VendorProductVersions
Linux Linux 433042a91f9373241307725b52de573933ffedbf – before 939c4e33005e2a56ea8fcedddf0da92df864bd3b4f1fffa2376922f3d1d506e49c0fd445b023a28e – before 327f89c21601ebb7889f8c97754b76f08ce95a0c4f1fffa2376922f3d1d506e49c0fd445b023a28e – before b556c278d43f4707a9073ca74d55581b4f2798064f1fffa2376922f3d1d506e49c0fd445b023a28e – before 5c76f9961c170552c1d07c830b5e1454751516006.6.32 – before 6.6.117
Linux Linux 6.8

References