CVE-2026-63909: Linux Kernel: sınır dışı okuma

Açıklama (NVD)

In the Linux kernel, the following vulnerability has been resolved: ksmbd: OOB read regression in smb_check_perm_dacl() ACE-walk loops Commit d07b26f39246 ("ksmbd: require minimum ACE size in smb_check_perm_dacl()") introduced a transposed bounds check: if (offsetof(struct smb_ace, sid) + aces_size < CIFS_SID_BASE_SIZE) Since offsetof(..sid) is 8 and CIFS_SID_BASE_SIZE is 8, this evaluates to `aces_size < 0`. Because `aces_size` is always non-negative, this check becomes dead code and never breaks the loop. Worse, that commit removed the old 4-byte guard, meaning the loop now reads `ace->size` (offset 2) even when `aces_size` is 0-3 bytes. This re-opens a 2-byte heap out-of-bounds (OOB) read past the pntsd allocation during subsequent SMB2_CREATE operations. Fix this by properly transposing the comparison to require at least 16 bytes (8-byte offset + 8-byte SID base), matching the correct form used in smb_inherit_dacl().

Özet bilgiler

Ürün

Linux Linux Kernel

CVSS v3.1

8.1 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H

EPSS

%0,63 (yüzdelik 50)

CWE

CWE-125

Yama

Mevcut

Etkilenen sürümler

Kaynaklar

• NVD kaydı
• git.kernel.org
• git.kernel.org
• git.kernel.org
• git.kernel.org
• git.kernel.org
• git.kernel.org
• git.kernel.org
• CWE-125