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CVE-2026-31704

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

Description (CNA)

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 (CNA)

Vendor / productVersions
Linux / Linuxaffected e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 before 41e53a773db6342ac9a689ee5ba635c31744c9f0; affected e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 before 8d5729350b236896f51379588d9a690b7fafb8db; affected e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 before e1955a94b6f17f4b058afa955a6f187eb3ed7615; affected e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 before 5e7b8f3c539d69b2ed5f2408e2f75e68ce7eef43; affected e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 before ef7902be3f215b6bf7babe4dc9dd9a7d57dad7a7; affected e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 before 299f962c0b02d048fb45d248b4da493d03f3175d
Linux / Linuxaffected 5.15; unaffected 0 before 5.15; unaffected 6.1.175 through 6.1.*; unaffected 6.6.136 through 6.6.*; unaffected 6.12.84 through 6.12.*; unaffected 6.18.25 through 6.18.*; unaffected 7.0.2 through 7.0.*; unaffected 7.1 through *

CWE

No CWE identifiers supplied.

References

ADP enrichment

siemens-SADP

No English description supplied.