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CVE-2026-93282— ksmbd: fix maximum allowed access checks

Quick assessment

Affected
Linux Linux
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

在 Linux 内核中,已修复以下漏洞: ksmbd:修正最大允许访问权限的检查逻辑 DACL(离散访问控制列表)权限检查会查找与当前用户匹配的 ACE(访问控制条目),若无匹配则回退到 Everyone(所有人)ACE。然而,该逻辑未考虑 Authenticated Users(已认证用户)ACE。实际上,任何已认证会话的成员均属于该知名组(S-1-5-11)。 因此,当通过 S-1-5-11(Authenticated Users 组)授予访问权限的文件被打开时,可能错误地返回 STATUS_ACCESS_DE

CVSS 8.1 · High EPSS 0.31% · P21

Affected Version Matrix 6

VendorProduct Version RangeStatus
Linux Linux e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9< 35d5c59fe6b1d9fe43fb14eb384f69ee1a120f9c affected
e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9< cc2f133e80eb2c4a04bfa77a2f207749fe2f516a affected
5.15 affected
< 5.15 unaffected
7.2.6≤ 7.2.* unaffected
7.3-rc1≤ * unaffected
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I. Basic Information for CVE-2026-93282

Vulnerability Information

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Vulnerability Title
ksmbd: fix maximum allowed access checks
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: ksmbd: fix maximum allowed access checks The DACL permission check looks for an ACE matching the current user and falls back to the Everyone ACE. It does not consider an Authenticated Users ACE, even though an authenticated session is a member of that well-known group. As a result, opening a file whose access is granted through S-1-5-11 can incorrectly fail with STATUS_ACCESS_DENIED. Treat an Authenticated Users ACE as a fallback entry alongside Everyone. The maximal access calculation also combines access masks from every ACE, regardless of whether its SID applies to the current user. This can grant rights belonging to an unrelated principal. Process only ACEs applying to the user, Everyone, or Authenticated Users, and accumulate allowed and denied masks in ACL order. Preserve explicitly requested access bits so they are validated against the resulting maximal mask. When ACCESS_SYSTEM_SECURITY is denied, report STATUS_PRIVILEGE_NOT_HELD instead of the generic STATUS_ACCESS_DENIED. Access to the system ACL requires a security privilege that ksmbd does not grant. For regular files, include FILE_EXECUTE in maximal access when the client requested GENERIC_EXECUTE and the DACL grants the complete file-read set. Keep a direct FILE_EXECUTE request subject to the explicit DACL bit. This matches the POSIX file ACL mapping without broadening specific execute requests. Do not replace rights from an applicable NT ACE with a POSIX ACL entry. The POSIX ACL is only a fallback when no user, Everyone, or Authenticated Users ACE applies; otherwise it can incorrectly broaden the stored DACL. This fixes smb2.maximum_allowed.maximum_allowed.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
Source: CVE Program / CVE List V5
Vulnerability Type
N/A
Source: CVE Program / CVE List V5

Affected Products

Vendor Product Affected Versions CPE Subscribe
Linux Linux e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 ~ 35d5c59fe6b1d9fe43fb14eb384f69ee1a120f9c -
Linux Linux 5.15 -

II. Public POCs for CVE-2026-93282

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III. Intelligence Information for CVE-2026-93282

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Patches & Fixes for CVE-2026-93282 (2)

Same Patch Batch · Linux · 2026-09-24 · 234 CVEs total

CVE-2026-93207 9.8 CRITICAL SUNRPC: Zero rpc_gss_wire_cred at svcauth_gss_decode_credbody() entry
CVE-2026-97413 9.8 CRITICAL RDMA/rtrs-srv: Fix integer underflow in process_read and process_write
CVE-2026-93228 9.1 CRITICAL svcrdma: Reject Write/Reply chunks with segcount 0
CVE-2026-93793 8.8 HIGH wifi: iwlwifi: mvm: validate TX_CMD response layout
CVE-2026-93799 8.8 HIGH wifi: iwlwifi: mvm: validate sta_id in BA window status notif
CVE-2026-93790 8.8 HIGH wifi: iwlwifi: mvm: fix out-of-bounds tid_data access in BA notif
CVE-2026-93806 8.8 HIGH wifi: cfg80211: validate assoc response length before status and IE access
CVE-2026-97442 8.8 HIGH wifi: ath11k: fix invalid data access in ath11k_dp_rx_h_undecap_nwifi
CVE-2026-97509 8.8 HIGH thunderbolt: Keep XDomain reference during the lifetime of a service
CVE-2026-97409 8.8 HIGH nvme-fc: Do not cancel requests in io target before it is initialized
CVE-2026-93280 8.8 HIGH greybus: audio: bound the topology section sizes against the fetched size
CVE-2026-93284 8.8 HIGH drm/pagemap: dma-unmap pages before handling migration errors
CVE-2026-97451 8.4 HIGH ACPICA: Fix integer overflow in acpi_ex_opcode_3A_1T_1R() (mid_op)
CVE-2026-97455 8.4 HIGH ACPICA: Fix use-after-free in acpi_ds_terminate_control_method()
CVE-2026-97452 8.4 HIGH ACPICA: Prevent adding invalid references
CVE-2026-97450 8.4 HIGH ACPICA: validate handler object type in two places
CVE-2026-93827 8.4 HIGH virtio-fs: avoid double-free on failed queue setup
CVE-2026-97433 8.2 HIGH nvme: validate FDP configuration descriptor sizes
CVE-2026-93786 8.1 HIGH ksmbd: preserve VFS inherited POSIX ACL mask
CVE-2026-93221 8.1 HIGH nfsd: convert nfsd_net boolean flags to unsigned long flags word

Showing top 20 of 234 CVEs. View all on vendor page &rarr; →

IV. Related Vulnerabilities

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