CVE-2023-52434: smb: client: fix potential OOBs in smb2_parse_contexts()

Severity: high (CVSS 8.0 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.0% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2024-02-20 · updated 2026-08-04
Weakness: CWE-119

Description

In the Linux kernel, the following vulnerability has been resolved: smb: client: fix potential OOBs in smb2_parse_contexts() Validate offsets and lengths before dereferencing create contexts in smb2_parse_contexts(). This fixes following oops when accessing invalid create contexts from server: BUG: unable to handle page fault for address: ffff8881178d8cc3 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 4a01067 P4D 4a01067 PUD 0 Oops: 0000 [#1] PREEMPT SMP NOPTI CPU: 3 PID: 1736 Comm: mount.cifs Not tainted 6.7.0-rc4 #1 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.16.2-3-gd478f380-rebuilt.opensuse.org 04/01/2014 RIP: 0010:smb2_parse_contexts+0xa0/0x3a0 [cifs] Code: f8 10 75 13 48 b8 93 ad 25 50 9c b4 11 e7 49 39 06 0f 84 d2 00 00 00 8b 45 00 85 c0 74 61 41 29 c5 48 01 c5 41 83 fd 0f 76 55 <0f> b7 7d 04 0f b7 45 06 4c 8d 74 3d 00 66 83 f8 04 75 bc ba 04 00 RSP: 0018:ffffc900007939e0 EFLAGS: 00010216 RAX: ffffc90000793c78 RBX: ffff8880180cc000 RCX: ffffc90000793c90 RDX: ffffc90000793cc0 RSI: ffff8880178d8cc0 RDI: ffff8880180cc000 RBP: ffff8881178d8cbf R08: ffffc90000793c22 R09: 0000000000000000 R10: ffff8880180cc000 R11: 0000000000000024 R12: 0000000000000000 R13: 0000000000000020 R14: 0000000000000000 R15: ffffc90000793c22 FS: 00007f873753cbc0(0000) GS:ffff88806bc00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffff8881178d8cc3 CR3: 00000000181ca000 CR4: 0000000000750ef0 PKRU: 55555554 Call Trace: <TASK> ? __die+0x23/0x70 ? page_fault_oops+0x181/0x480 ? search_module_extables+0x19/0x60 ? srso_alias_return_thunk+0x5/0xfbef5 ? exc_page_fault+0x1b6/0x1c0 ? asm_exc_page_fault+0x26/0x30 ? smb2_parse_contexts+0xa0/0x3a0 [cifs] SMB2_open+0x38d/0x5f0 [cifs] ? smb2_is_path_accessible+0x138/0x260 [cifs] smb2_is_path_accessible+0x138/0x260 [cifs] cifs_is_path_remote+0x8d/0x230 [cifs] cifs_mount+0x7e/0x350 [cifs] cifs_smb3_do_mount+0x128/0x780 [cifs] smb3_get_tree+0xd9/0x290 [cifs] vfs_get_tree+0x2c/0x100 ? capable+0x37/0x70 path_mount+0x2d7/0xb80 ? srso_alias_return_thunk+0x5/0xfbef5 ? _raw_spin_unlock_irqrestore+0x44/0x60 __x64_sys_mount+0x11a/0x150 do_syscall_64+0x47/0xf0 entry_SYSCALL_64_after_hwframe+0x6f/0x77 RIP: 0033:0x7f8737657b1e

Affected products

Debian Linux: 10.0
Linux kernel: from 5.3 before 5.4.277; from 5.5 before 5.10.211; from 5.11 before 5.15.150; from 5.16 through 6.1.79; from 6.2 before 6.6.8; 6.7-rc1, 6.7-rc2, 6.7-rc3, 6.7-rc4, 6.7-rc5 — fixed in 5.10.211, 5.15.150, 5.4.277, 6.6.8

How to fix

Upgrade to a fixed version: Linux kernel 5.10.211, 5.15.150, 5.4.277, 6.6.8. Check the vendor advisory for mitigations.

References

Get alerted when CVE-2023-52434 or the next vulnerability affects your stack