CVE-2026-97437

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.

Affected Software

References

• https://git.kernel.org/stable/c/0505f1e7bb5b981b6ed62d98b26ddce76142865d
• https://git.kernel.org/stable/c/2f7d0ec8c10dc7bf7a8c9a9cb169f9a4d1fac2ba
• https://git.kernel.org/stable/c/6a8149a20e46086c756c2a9202e377c0b649a0c3
• https://git.kernel.org/stable/c/aa1bdbb39f49c5bc9779316891c40005517842a5
• https://git.kernel.org/stable/c/d1f98938e437732c0ecdfc8ee451e12a072f6d07
• https://git.kernel.org/stable/c/ed6da1abeec50db9060d714f03743fe0b63e4fe4