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Vulnerability · Published Sep 15, 2025 · Assigned by Linux

CVE-2023-53246cifs: fix DFS traversal oops without CONFIG_CIFS_DFS_UPCALL

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

Severity (CVSS NVD)5.5Medium
Exploit odds (30 days)0.1%top 96.0% 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: cifs: fix DFS traversal oops without CONFIG_CIFS_DFS_UPCALL When compiled with CONFIG_CIFS_DFS_UPCALL disabled, cifs_dfs_d_automount is NULL. cifs.ko logic for mapping CIFS_FATTR_DFS_REFERRAL attributes to S_AUTOMOUNT and corresponding dentry flags is retained regardless of CONFIG_CIFS_DFS_UPCALL, leading to a NULL pointer dereference in VFS follow_automount() when traversing a DFS referral link: BUG: kernel NULL pointer dereference, address: 0000000000000000 ... Call Trace: <TASK> __traverse_mounts+0xb5/0x220 ? cifs_revalidate_mapping+0x65/0xc0 [cifs] step_into+0x195/0x610 ? lookup_fast+0xe2/0xf0 path_lookupat+0x64/0x140 filename_lookup+0xc2/0x140 ? __create_object+0x299/0x380 ? kmem_cache_alloc+0x119/0x220 ? user_path_at_empty+0x31/0x50 user_path_at_empty+0x31/0x50 __x64_sys_chdir+0x2a/0xd0 ? exit_to_user_mode_prepare+0xca/0x100 do_syscall_64+0x42/0x90 entry_SYSCALL_64_after_hwframe+0x72/0xdc This fix adds an inline cifs_dfs_d_automount() {return -EREMOTE} handler when CONFIG_CIFS_DFS_UPCALL is disabled. An alternative would be to avoid flagging S_AUTOMOUNT, etc. without CONFIG_CIFS_DFS_UPCALL. This approach was chosen as it provides more control over the error path.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:12linux6.1.25-1DEBIAN-CVE-2023-53246
Debian:13linux6.1.25-1DEBIAN-CVE-2023-53246
Debian:14linux6.1.25-1DEBIAN-CVE-2023-53246
Ubuntu:22.04:LTSlinux5.15.0-79.86UBUNTU-CVE-2023-53246
Ubuntu:22.04:LTSlinux-allwinner-5.19no fix listedUBUNTU-CVE-2023-53246
Ubuntu:22.04:LTSlinux-aws5.15.0-1042.47UBUNTU-CVE-2023-53246
Ubuntu:22.04:LTSlinux-aws-5.19no fix listedUBUNTU-CVE-2023-53246
Ubuntu:22.04:LTSlinux-aws-6.2no fix listedUBUNTU-CVE-2023-53246
Ubuntu:22.04:LTSlinux-aws-6.5no fix listedUBUNTU-CVE-2023-53246
Ubuntu:22.04:LTSlinux-azure5.15.0-1045.52UBUNTU-CVE-2023-53246
Ubuntu:22.04:LTSlinux-azure-5.19no fix listedUBUNTU-CVE-2023-53246
Ubuntu:24.04:LTSlinux-azure-6.11no fix listedUBUNTU-CVE-2023-53246
Ubuntu:22.04:LTSlinux-azure-6.2no fix listedUBUNTU-CVE-2023-53246
Ubuntu:22.04:LTSlinux-azure-6.5no fix listedUBUNTU-CVE-2023-53246
Ubuntu:22.04:LTSlinux-azure-fde5.15.0-1045.52.1UBUNTU-CVE-2023-53246
Ubuntu:22.04:LTSlinux-azure-fde-5.19no fix listedUBUNTU-CVE-2023-53246
Ubuntu:22.04:LTSlinux-azure-fde-6.2no fix listedUBUNTU-CVE-2023-53246
Ubuntu:22.04:LTSlinux-gcp5.15.0-1039.47UBUNTU-CVE-2023-53246
Ubuntu:22.04:LTSlinux-gcp-5.19no fix listedUBUNTU-CVE-2023-53246
Ubuntu:24.04:LTSlinux-gcp-6.11no fix listedUBUNTU-CVE-2023-53246
Ubuntu:22.04:LTSlinux-gcp-6.2no fix listedUBUNTU-CVE-2023-53246
Ubuntu:22.04:LTSlinux-gcp-6.5no fix listedUBUNTU-CVE-2023-53246
Ubuntu:22.04:LTSlinux-gke5.15.0-1039.44UBUNTU-CVE-2023-53246
Ubuntu:22.04:LTSlinux-gkeop5.15.0-1025.30UBUNTU-CVE-2023-53246
Ubuntu:22.04:LTSlinux-hwe-5.19no fix listedUBUNTU-CVE-2023-53246
Ubuntu:24.04:LTSlinux-hwe-6.11no fix listedUBUNTU-CVE-2023-53246
Ubuntu:22.04:LTSlinux-hwe-6.2no fix listedUBUNTU-CVE-2023-53246
Ubuntu:22.04:LTSlinux-hwe-6.5no fix listedUBUNTU-CVE-2023-53246
Ubuntu:22.04:LTSlinux-ibm5.15.0-1035.38UBUNTU-CVE-2023-53246
Ubuntu:24.04:LTSlinux-intelno fix listedUBUNTU-CVE-2023-53246
Ubuntu:22.04:LTSlinux-intel-iot-realtimeno fix listedUBUNTU-CVE-2023-53246
Ubuntu:22.04:LTSlinux-intel-iotg5.15.0-1037.42UBUNTU-CVE-2023-53246
Ubuntu:22.04:LTSlinux-kvm5.15.0-1039.44UBUNTU-CVE-2023-53246
Ubuntu:22.04:LTSlinux-lowlatency5.15.0-79.88UBUNTU-CVE-2023-53246
Ubuntu:22.04:LTSlinux-lowlatency-hwe-5.19no fix listedUBUNTU-CVE-2023-53246
Ubuntu:24.04:LTSlinux-lowlatency-hwe-6.11no fix listedUBUNTU-CVE-2023-53246
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.2no fix listedUBUNTU-CVE-2023-53246
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.5no fix listedUBUNTU-CVE-2023-53246
Ubuntu:22.04:LTSlinux-nvidia5.15.0-1030.30UBUNTU-CVE-2023-53246
Ubuntu:22.04:LTSlinux-nvidia-6.2no fix listedUBUNTU-CVE-2023-53246
Ubuntu:22.04:LTSlinux-nvidia-6.5no fix listedUBUNTU-CVE-2023-53246
Ubuntu:22.04:LTSlinux-nvidia-tegra5.15.0-1016.16UBUNTU-CVE-2023-53246
Ubuntu:22.04:LTSlinux-nvidia-tegra-igx5.15.0-1002.2UBUNTU-CVE-2023-53246
Ubuntu:22.04:LTSlinux-oem-5.17no fix listedUBUNTU-CVE-2023-53246
Ubuntu:22.04:LTSlinux-oem-6.0no fix listedUBUNTU-CVE-2023-53246
Ubuntu:22.04:LTSlinux-oem-6.1no fix listedUBUNTU-CVE-2023-53246
Ubuntu:24.04:LTSlinux-oem-6.11no fix listedUBUNTU-CVE-2023-53246
Ubuntu:22.04:LTSlinux-oem-6.5no fix listedUBUNTU-CVE-2023-53246
Ubuntu:24.04:LTSlinux-oem-6.8no fix listedUBUNTU-CVE-2023-53246
Ubuntu:22.04:LTSlinux-oracle5.15.0-1040.46UBUNTU-CVE-2023-53246
Ubuntu:22.04:LTSlinux-oracle-6.5no fix listedUBUNTU-CVE-2023-53246
Ubuntu:22.04:LTSlinux-raspi5.15.0-1035.38UBUNTU-CVE-2023-53246
Ubuntu:24.04:LTSlinux-raspi-realtimeno fix listedUBUNTU-CVE-2023-53246
Ubuntu:22.04:LTSlinux-realtimeno fix listedUBUNTU-CVE-2023-53246
Ubuntu:24.04:LTSlinux-realtimeno fix listedUBUNTU-CVE-2023-53246
Ubuntu:22.04:LTSlinux-riscvno fix listedUBUNTU-CVE-2023-53246
Ubuntu:24.04:LTSlinux-riscvno fix listedUBUNTU-CVE-2023-53246
Ubuntu:22.04:LTSlinux-riscv-5.19no fix listedUBUNTU-CVE-2023-53246
Ubuntu:22.04:LTSlinux-riscv-6.5no fix listedUBUNTU-CVE-2023-53246
Ubuntu:22.04:LTSlinux-starfive-5.19no fix listedUBUNTU-CVE-2023-53246
Ubuntu:22.04:LTSlinux-starfive-6.2no fix listedUBUNTU-CVE-2023-53246
Ubuntu:22.04:LTSlinux-starfive-6.5no fix listedUBUNTU-CVE-2023-53246
Ubuntu:22.04:LTSlinux-xilinx-zynqmp5.15.0-1025.29UBUNTU-CVE-2023-53246

Affected products (as reported)

VendorProductVersions
Linux Linux 25e195aa1e607f129ab912d29fcfc79239703307 – before 26a32a212bc540f4773cd6af8cf73e967d72569c25e195aa1e607f129ab912d29fcfc79239703307 – before b64305185b76f1d5145ce594ff48f3f0e70695bd25e195aa1e607f129ab912d29fcfc79239703307 – before b7d854c33ab48e55fc233699bbefe39ec9bb5c0525e195aa1e607f129ab912d29fcfc79239703307 – before 1e144b68208e98fd4602c842a7149ba5f41d87fb25e195aa1e607f129ab912d29fcfc79239703307 – before 179a88a8558bbf42991d361595281f3e45d7edfc
Linux Linux 5.7

References