CVE-2023-53246 [Medium] | Security Vulnerability in Linux Kernel

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.

#	Date	Old EPSS score	New EPSS score	Delta (New - Old)
1	2026-06-15	0.02%	0.14%	+0.11%
2	2025-09-16	—	0.02%	—

Date

Old EPSS score

New EPSS score

Delta (New - Old)

2026-06-15

0.02%

0.14%

+0.11%

2025-09-16

—

0.02%

—

Base score	Version	Severity	Vector	Exploitability	Impact	Score source
5.5	3.1	MEDIUM	`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H` Click to expand Attack vector (AV:L) They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by. Attack complexity (AC:L) Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup. Privileges required (PR:L) A normal user session is enough; they don’t have to be admin. User interaction (UI:N) Nobody has to click “OK” or open a trap file; it can work without a victim helping. Scope (S:U) Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems. Confidentiality (C:N) Doesn’t really leak secrets in a meaningful way. Integrity (I:N) Data isn’t meaningfully altered or forged. Availability (A:H) Could take the service down hard or make it unusable for people who depend on it.	1.8	3.6	[email protected]

Base score

Version

Severity

Vector

Exploitability

Impact

Score source

5.5

3.1

MEDIUM

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H Click to expand

Attack vector (AV:L): They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
Attack complexity (AC:L): Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L): A normal user session is enough; they don’t have to be admin.
User interaction (UI:N): Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U): Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N): Doesn’t really leak secrets in a meaningful way.
Integrity (I:N): Data isn’t meaningfully altered or forged.
Availability (A:H): Could take the service down hard or make it unusable for people who depend on it.

1.8

3.6

[email protected]

OS Trackers for CVE-2023-53246

vendor	priority	summary	link
`debian`	not yet assigned	CVE-2023-53246 not yet assigned priority: Debian including 1 source packages (linux), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5.	https://security-tracker.debian.org/tracker/CVE-2023-53246
`redhat`	low	—	https://access.redhat.com/security/cve/CVE-2023-53246
`suse`	medium	—	https://www.suse.com/security/cve/CVE-2023-53246/
`ubuntu`	medium	CVE-2023-53246 medium priority: Ubuntu including 158 source packages (linux, linux-allwinner-5.19, …), 1414 status rows across 9 suites (bionic, focal, jammy, noble, plucky, questing, trusty, upstream, xenial): DNE 1017, ignored 162, released 138, not-affected 76, needed 20, needs-triage 1.	https://ubuntu.com/security/CVE-2023-53246

Affected software / configurations for CVE-2023-53246

Vendor	Product	Version	Raw CPE
linux	linux_kernel	< 4.14.312	cpe:2.3:o:linux:linux_kernel::::::::
linux	linux_kernel	>= 4.15, < 4.19.280	cpe:2.3:o:linux:linux_kernel::::::::
linux	linux_kernel	>= 4.20, < 5.4.240	cpe:2.3:o:linux:linux_kernel::::::::
linux	linux_kernel	>= 5.5, < 5.10.177	cpe:2.3:o:linux:linux_kernel::::::::
linux	linux_kernel	>= 5.11, < 5.15.106	cpe:2.3:o:linux:linux_kernel::::::::
linux	linux_kernel	>= 5.16, < 6.1.23	cpe:2.3:o:linux:linux_kernel::::::::
linux	linux_kernel	>= 6.2, < 6.2.10	cpe:2.3:o:linux:linux_kernel::::::::
linux	linux_kernel	6.3	cpe:2.3:o:linux:linux_kernel:6.3:rc1::::::
linux	linux_kernel	6.3	cpe:2.3:o:linux:linux_kernel:6.3:rc2::::::
linux	linux_kernel	6.3	cpe:2.3:o:linux:linux_kernel:6.3:rc3::::::
linux	linux_kernel	6.3	cpe:2.3:o:linux:linux_kernel:6.3:rc4::::::

References for CVE-2023-53246

URL	Tags
https://git.kernel.org/stable/c/179a88a8558bbf42991d361595281f3e45d7edfc	Patch
https://git.kernel.org/stable/c/1e144b68208e98fd4602c842a7149ba5f41d87fb	Patch
https://git.kernel.org/stable/c/26a32a212bc540f4773cd6af8cf73e967d72569c	Patch
https://git.kernel.org/stable/c/b64305185b76f1d5145ce594ff48f3f0e70695bd	Patch
https://git.kernel.org/stable/c/b7d854c33ab48e55fc233699bbefe39ec9bb5c05	Patch

URL

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

Exploit prediction scoring system (EPSS) score for CVE-2023-53246

Common vulnerability scoring system (CVSS) metrics for CVE-2023-53246

Weakness enumeration for CVE-2023-53246

OS Trackers for CVE-2023-53246

Affected software / configurations for CVE-2023-53246

References for CVE-2023-53246