CVE-2026-89779

Summary

In the Linux kernel, the following vulnerability has been resolved:

fs/ntfs3: validate ef->size covers the record's name and value

When an EA record has a non-zero ef->size, ntfs_read_ea() only checks that the record fits in the remaining buffer (ea_size > bytes), not that ef->size is large enough to hold the record's own name_len + 1 + elength.

A crafted image can pass validation with, e.g., ef->size = 24 but elength = 0xffff. ntfs_get_ea() then trusts elength and copies it out of the undersized record, reading past the kmalloc(info->size) allocation and leaking heap memory to userspace via getxattr():

BUG: KASAN: slab-out-of-bounds in ntfs_get_ea (fs/ntfs3/xattr.c:302) Read of size 65535 at addr ffff888100794550 by task exploit __asan_memcpy (mm/kasan/shadow.c:105) ntfs_get_ea (fs/ntfs3/xattr.c:302) ntfs_getxattr (fs/ntfs3/xattr.c:848) __vfs_getxattr (fs/xattr.c:441) vfs_getxattr (fs/xattr.c:474) do_getxattr (fs/xattr.c:800) path_getxattrat (fs/xattr.c:868) do_syscall_64 (arch/x86/entry/syscall_64.c:94)

The buggy address is located 80 bytes inside of allocated 84-byte region in cache kmalloc-96

Compute the size the record needs and require ef->size to cover it.

Affected Software

Weaknesses

References

• https://git.kernel.org/stable/c/b27e68ad818a4ca2cef8f35f97e75d756714c818
• https://git.kernel.org/stable/c/28a924c7e67e6d71abeb04860b61166fecb027fc
• https://git.kernel.org/stable/c/d585ed08308909c7e6fefb4e8a258aeb29b19ff9
• https://git.kernel.org/stable/c/077df8464cf24f8ffc82fb6efec2ae600686e699
• https://git.kernel.org/stable/c/aab1880058ac767d3ea9388a9a7221c776c22c44
• https://git.kernel.org/stable/c/c8a109c9e23a2c7fd548473dde728b2cb8188146
• https://git.kernel.org/stable/c/c22f91d82cb9a29d22bdffdce6c803467984ad0c

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