CVE-2023-53246

published 2025-09-15

CVE-2023-53246: In the Linux kernel, the following vulnerability has been resolved: cifs: fix DFS traversal oops without CONFIG_CIFS_DFS_UPCALL When compiled with…

Priority P4 19 medium 5.5 CVSS 3.1

AV L AC L PR L UI N S U C N I N A H

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:

__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

19 ranges

Vendor	Product	Version range	Fixed in
debian	linux	< linux 6.1.25-1 (bookworm)	linux 6.1.25-1 (bookworm)
linux	linux	—	—
linux	linux	>= 25e195aa1e607f129ab912d29fcfc79239703307 < 26a32a212bc540f4773cd6af8cf73e967d72569c	26a32a212bc540f4773cd6af8cf73e967d72569c
linux	linux	>= 25e195aa1e607f129ab912d29fcfc79239703307 < b64305185b76f1d5145ce594ff48f3f0e70695bd	b64305185b76f1d5145ce594ff48f3f0e70695bd
linux	linux	>= 25e195aa1e607f129ab912d29fcfc79239703307 < b7d854c33ab48e55fc233699bbefe39ec9bb5c05	b7d854c33ab48e55fc233699bbefe39ec9bb5c05
linux	linux	>= 25e195aa1e607f129ab912d29fcfc79239703307 < 1e144b68208e98fd4602c842a7149ba5f41d87fb	1e144b68208e98fd4602c842a7149ba5f41d87fb
linux	linux	>= 25e195aa1e607f129ab912d29fcfc79239703307 < 179a88a8558bbf42991d361595281f3e45d7edfc	179a88a8558bbf42991d361595281f3e45d7edfc
linux	linux_kernel	< 4.14.312	4.14.312
linux	linux_kernel	—	—
linux	linux_kernel	>= 0 < 5.10.178-1	5.10.178-1
linux	linux_kernel	>= 0 < 6.1.25-1	6.1.25-1
linux	linux_kernel	>= 0 < 6.1.25-1	6.1.25-1
linux	linux_kernel	>= 0 < 6.1.25-1	6.1.25-1
linux	linux_kernel	>= 4.15 < 4.19.280	4.19.280
linux	linux_kernel	>= 4.20 < 5.4.240	5.4.240
linux	linux_kernel	>= 5.11 < 5.15.106	5.15.106
linux	linux_kernel	>= 5.16 < 6.1.23	6.1.23
linux	linux_kernel	>= 5.5 < 5.10.177	5.10.177
linux	linux_kernel	>= 6.2 < 6.2.10	6.2.10

CVSS provenance

nvd v3.1 5.5 MEDIUM CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

osv 5.5 MEDIUM

vendor_debian 5.5 MEDIUM

vendor_redhat 5.5 MEDIUM

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