Out-of-bounds SMB access in macOS Kernel pre-Sequoia 15.8
CVE-2026-84543 Published on September 14, 2026
An out-of-bounds access issue was addressed with improved bounds checking. This issue is fixed in macOS Golden Gate 27, macOS Sequoia 15.8, macOS Tahoe 26.7. Connecting to a malicious SMB server may cause unexpected system termination or corrupt kernel memory.
Vulnerability Analysis
CVE-2026-84543 can be exploited with network access, and does not require authorization privileges or user interaction. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to have no impact on confidentiality, a high impact on integrity, and no impact on availability.
Weakness Type
Out-of-bounds Read
The software reads data past the end, or before the beginning, of the intended buffer. Typically, this can allow attackers to read sensitive information from other memory locations or cause a crash. A crash can occur 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. The expected sentinel might not be located in the out-of-bounds memory, causing excessive data to be read, leading to a segmentation fault or a buffer overflow. The software may modify an index or perform pointer arithmetic that references a memory location that is outside of the boundaries of the buffer. A subsequent read operation then produces undefined or unexpected results.
Products Associated with CVE-2026-84543
Want to know whenever a new CVE is published for Apple macOS? stack.watch will email you.
Affected Versions
Apple macOS:- Before 15.8 is affected.
- Before 26.7 is affected.
- Before 27 is affected.