CVE-2026-53390
Description
A flaw was found in the Linux kernel's ksmbd component. An authenticated client can exploit an out-of-bounds read vulnerability in the smb_check_perm_dacl() function by providing a specially crafted Access Control Entry (ACE). This crafted ACE, when processed during an access check on a share that uses ACL extended attributes, can lead to a heap out-of-bounds read. The primary consequence of this vulnerability is information disclosure, where sensitive data beyond the intended memory boundary may be exposed.
Understanding the Weakness (CWE)
Confidentiality
Technical Impact: Read Memory
An attacker could get secret values such as cryptographic keys, PII, memory addresses, or other information that could be used in additional attacks.
Confidentiality
Technical Impact: Bypass Protection Mechanism
Out-of-bounds memory could contain memory addresses or other information that can be used to bypass ASLR and other protection mechanisms in order to improve the reliability of exploiting a separate weakness for code execution.
Availability
Technical Impact: DoS: Crash, Exit, or Restart
An attacker could cause a segmentation fault or crash by causing memory to be read outside of the bounds of the buffer. This is especially likely when the code reads a variable amount of data and assumes that a sentinel exists to stop the read operation, such as a NUL in a string.
Other
Technical Impact: Varies by Context
The read operation could produce other undefined or unexpected results.
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