Out-of-bounds write in Linux kernel - CVE-2026-64431
Published: July 27, 2026
Vulnerability identifier: #VU139510
CSH Severity: Low
CVSS v4: 6.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-64431
CWE-ID: CWE-787
Exploitation vector: Local access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a local user to cause a denial of service.
The vulnerability exists due to an out-of-bounds memory access in post_write_mst_fixup() in the NTFS index handling code when processing a crafted NTFS image containing an invalid index_block. A local user can supply a malicious NTFS image with crafted index_block metadata to cause a denial of service.
The issue can be triggered by malformed usa_ofs or usa_count values, including values that cause integer underflow or reference data outside the ntfs_record.
Affected software
Linux kernel
How to mitigate CVE-2026-64431
Install security update from vendor's repository.
Linux kernel - update to 7.0 rc3