CVE-2026-72195

Summary

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

fs/ntfs3: bound attr_off in UpdateResidentValue against data_off

In do_action()'s UpdateResidentValue case (fslog.c:3307), lrh->attr_off and lrh->redo_len come from the on-disk LRH. When they satisfy aoff + dlen < attr->res.data_off, the assignment

attr->res.data_size = cpu_to_le32(aoff + dlen - data_off);

underflows to ~4 GiB (e.g. 0xFFFFFFF9 when aoff=0x10, dlen=1, data_off=0x18). Subsequent code that reads attr->res.data_size to walk the resident attribute payload would then read up to 4 GiB past the 1024-byte MFT record allocation.

The existing mi_enum_attr() defense in fs/ntfs3/record.c:287 catches the corrupted data_size on the next attribute walk and fails the mount, but only on the path that walks all attributes. A read site that picks an attribute by name and reads its data_size without re-validating is not covered. Validate aoff against data_off and asize at the source.

Reproduced under UML+KASAN on mainline 8d90b09e6741 via pr_warn-only probe: with aoff=0x10 and data_off=0x18, the post-assignment data_size is 0xfffffff9 (mount then fails at -22 from mi_enum_attr).

[almaz.alexandrovich@paragon-software.com: clang-formatted the changes]

Affected Software

Weaknesses

References

• https://git.kernel.org/stable/c/ab8761676d638c5be170aaf91b7ffdd451236616
• https://git.kernel.org/stable/c/53c12f178f584dc5f836ffe2782138a6e9348ed9
• https://git.kernel.org/stable/c/546518468e6c9ea469669eef78f8cc380ad6e2ca
• https://git.kernel.org/stable/c/97758fd9756b5f09e9ddc6a5f6a569041acc8421
• https://git.kernel.org/stable/c/50b5e83384e7fed3d11d18b79ff350e9d6d89861
• https://git.kernel.org/stable/c/a89c66674283a0293c0f266dc57087a6114371a3
• https://git.kernel.org/stable/c/d1570c48f49a693974d000251030370ee2e83539

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