CVE-2026-40706: ntfs-3g 2022.10.3: Heap buffer overflow

[Rostislav <rostislav () tuxera com>]

Hello oss-security,

A vulnerability in ntfs-3g (https://github.com/tuxera/ntfs-3g) has been 
reported to us by a third party.

Short description:
In NTFS-3G 2022.10.3, a heap buffer overflow exists in 
ntfs_build_permissions_posix() in acls.c that allows an attacker to 
corrupt heap memory in the SUID-root ntfs-3g binary by crafting a 
malicious NTFS image. The overflow is triggered on the READ path (stat, 
readdir, open) when processing a security descriptor with multiple 
ACCESS_DENIED ACEs containing WRITE_OWNER from distinct group SIDs.

CVSS 3.1: 7.8 (High) — AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

References:
CVE ID: CVE-2026-40706
Full advisory: 
https://github.com/tuxera/ntfs-3g/security/advisories/GHSA-4cwv-5285-63v9
Fixed version: https://github.com/tuxera/ntfs-3g/releases/tag/2026.2.25

Credits: reported by Andrea Bocchetti