CVE-2026-31704

Summary

In the Linux kernel, the following vulnerability has been resolved:

ksmbd: use check_add_overflow() to prevent u16 DACL size overflow

set_posix_acl_entries_dacl() and set_ntacl_dacl() accumulate ACE sizes in u16 variables. When a file has many POSIX ACL entries, the accumulated size can wrap past 65535, causing the pointer arithmetic (char *)pndace + *size to land within already-written ACEs. Subsequent writes then overwrite earlier entries, and pndacl->size gets a truncated value.

Use check_add_overflow() at each accumulation point to detect the wrap before it corrupts the buffer, consistent with existing check_mul_overflow() usage elsewhere in smbacl.c.

Affected Software

VendorProductVersion RangeStatus
LinuxLinuxe2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 < 41e53a773db6342ac9a689ee5ba635c31744c9f0affected
LinuxLinuxe2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 < 8d5729350b236896f51379588d9a690b7fafb8dbaffected
LinuxLinuxe2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 < e1955a94b6f17f4b058afa955a6f187eb3ed7615affected
LinuxLinuxe2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 < 5e7b8f3c539d69b2ed5f2408e2f75e68ce7eef43affected
LinuxLinuxe2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 < ef7902be3f215b6bf7babe4dc9dd9a7d57dad7a7affected
LinuxLinuxe2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 < 299f962c0b02d048fb45d248b4da493d03f3175daffected
LinuxLinux5.15affected
LinuxLinux0 < 5.15unaffected
LinuxLinux6.1.175 <= 6.1.*unaffected
LinuxLinux6.6.136 <= 6.6.*unaffected
LinuxLinux6.12.84 <= 6.12.*unaffected
LinuxLinux6.18.25 <= 6.18.*unaffected
LinuxLinux7.0.2 <= 7.0.*unaffected
LinuxLinux7.1 <= *unaffected

Weaknesses

References