CVE-2026-89781

Summary

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

fs/ntfs3: fix out-of-bounds read in read_log_rec_buf()

read_log_rec_buf() copies a log record into a caller buffer starting at

u32 off = lsn_to_page_off(log, lsn) + log->record_header_len;

log->record_header_len (and log->data_off, used for the following pages) comes verbatim from the on-disk restart area and is only checked for 8-byte alignment in is_rst_area_valid(), so off can exceed log->page_size. "tail = log->page_size - off" then underflows and memcpy() reads past the page_size-sized buffer returned by read_log_page(), spilling adjacent slab memory into the replay buffer.

This is reachable by mounting a crafted NTFS image:

BUG: KASAN: slab-out-of-bounds in read_log_rec_buf+0x216/0x580 Read of size 64 at addr ffff88800a877ff8 by task exploit/127 read_log_rec_buf fs/ntfs3/fslog.c:2299 log_replay fs/ntfs3/fslog.c:4216 ntfs_loadlog_and_replay fs/ntfs3/fsntfs.c:324 ntfs_fill_super fs/ntfs3/super.c:1392 get_tree_bdev_flags fs/super.c:1694 __x64_sys_mount fs/namespace.c:4360 The buggy address is located 4088 bytes to the right of the 4096-byte region [ffff88800a876000, ffff88800a877000)

Reject an in-page offset outside the current page before the copy.

[almaz.alexandrovich@paragon-software.com: replaced the >= sign with >]

Affected Software

Weaknesses

References

• https://git.kernel.org/stable/c/df099bfdb57773ba7f40f8a9dcc82e75af277922
• https://git.kernel.org/stable/c/1b2d31f1083beb80c55d1152249f652c1445a559
• https://git.kernel.org/stable/c/700973cc65db405bde0368ccf88699390150943e
• https://git.kernel.org/stable/c/49f7cbc902b08b56eb7d2633163ecc57a0e7145a
• https://git.kernel.org/stable/c/74a83aa05f73033af719771ab1f0c269928b4865
• https://git.kernel.org/stable/c/53e56f7aa1d0f950a8bc2e4cdb3ba9fe45967531
• https://git.kernel.org/stable/c/de603b9d377fab57a5e6432fa84a9f36b32c1636

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