CVE-2026-97437 ntfs3: fix out-of-bounds read in ntfs_dir_emit() and hdr_find_e()
A crafted NTFS image triggers an out-of-bounds read in the Linux kernel, potentially causing a crash or leaking memory contents.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2026-97437?
CVE-2026-97437 is a high-severity memory corruption vulnerability in Linux, published on 24 Sep 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Official description
In the Linux kernel, the following vulnerability has been resolved:
ntfs3: fix out-of-bounds read in ntfs_dir_emit() and hdr_find_e()
The bounds check in ntfs_dir_emit() compares fname->name_len (a character count) against e->size (a byte count) without accounting for the 2-byte-per-character UTF-16LE encoding or the ATTR_FILE_NAME header size:
if (fname->name_len + sizeof(struct NTFS_DE) > le16_to_cpu(e->size))
This computes: name_len + 16 > e_size
The correct check must account for the ATTR_FILE_NAME header (66 bytes before the name) and the UTF-16LE character size (2 bytes each):
sizeof(NTFS_DE) + offsetof(ATTR_FILE_NAME, name) + name_len * sizeof(short) > e_size
Which computes: 16 + 66 + name_len * 2 > e_size
The correct calculation already exists as fname_full_size() in ntfs.h and is used in cmp_fnames(), namei.c, and fslog.c, but was not used in the readdir path.
A crafted NTFS image with an index entry containing a small e->size but large fname->name_len bypasses the current check, causing ntfs_utf16_to_nls() to read past the entry boundary.
Additionally, add a key_size validation in hdr_find_e() to ensure the declared key_size does not exceed the available entry data, preventing comparison functions from reading past entry boundaries on the lookup path.
Which versions are affected by CVE-2026-97437?
How do I fix CVE-2026-97437?
Apply the vendor's patch.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2026-97437 being exploited?
There is no known exploitation of CVE-2026-97437 in the wild and no public exploit code.
Sources
Also known as AZL-103955, BELL-CVE-2026-97437, DEBIAN-CVE-2026-97437, GHSA-fpf4-vw37-hxfh, UBUNTU-CVE-2026-97437.