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CVE Record

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

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

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

This Linux kernel flaw affects the SMB/CIFS client. A malformed or hostile SMB server response can make the client read outside expected bounds and trigger a kernel crash during SMB mount or path access. The sources do not show active exploitation or a CVSS score.

Executive priority

Treat as a targeted patching priority for Linux systems that depend on SMB/CIFS. Urgency is higher where clients connect to third-party or less-trusted SMB servers; lower for isolated, fully trusted file-sharing environments.

Technical view

CVE-2023-52434 is an out-of-bounds access issue in smb2_parse_contexts(). The fix validates SMB2 create-context offsets and lengths before dereference. The reported failure is a kernel page fault in the cifs module reached through mount.cifs and SMB2_open.

Likely exposure

Exposure is most relevant to Linux systems that use the kernel CIFS/SMB client to mount or access SMB shares, especially where servers are untrusted, compromised, or externally managed.

Exploitation context

The provided record does not indicate KEV listing, public exploitation, or weaponized exploit availability. The described trigger is an invalid create context returned by an SMB server to a Linux client.

Researcher notes

Evidence supports memory-safety validation failure in the Linux SMB client, not a server-side Linux SMB flaw. Impact evidence is a kernel oops; broader confidentiality or code-execution impact is not established in the provided sources.

Mitigation direction

  • Apply Linux kernel updates containing the referenced stable SMB client fixes.
  • Use distribution security updates, including Debian LTS guidance where applicable.
  • Review NetApp advisory guidance if affected NetApp products are in scope.
  • Limit SMB/CIFS mounts to trusted servers and networks where feasible.
  • Monitor vendor advisories for exact fixed package versions.

Validation and detection

  • Inventory Linux hosts using CIFS/SMB mounts or mount.cifs.
  • Check running kernel versions against vendor fixed advisories.
  • Confirm the cifs kernel module is updated after patching.
  • Review logs for kernel oops or page faults involving cifs and smb2_parse_contexts().
  • Validate SMB mounts still function after kernel updates.
Prepared
Confidence
medium
Sources
10

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

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ATT&CK lookup starting points

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CVE-2023-52434 mapping review

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Vulnerability profileCVE Program record
Severity
Unknown
CVSS
Not scored
Known Exploited
No
Published
Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

0CVSS vectors
0Timeline events
0ADP providers
9Source links

CVSS and timeline data

No CVSS vectors or timeline events were available in the normalized CVE source material.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinuxb8c32dbb0deb287a5fcb78251e4eae6c7275760d, b8c32dbb0deb287a5fcb78251e4eae6c7275760d, b8c32dbb0deb287a5fcb78251e4eae6c7275760d, b8c32dbb0deb287a5fcb78251e4eae6c7275760d, b8c32dbb0deb287a5fcb78251e4eae6c7275760d, b8c32dbb0deb287a5fcb78251e4eae6c7275760dunaffected
LinuxLinux3.7, 0, 5.4.277, 5.10.211, 5.15.150, 6.1.79, 6.6.8, 6.7affected
Weakness

CWE details

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