CVE-2026-89640

HIGH

MEDIUM Priority: 0.01 BB Relevance: 39/100

Published: 2026-09-11 Modified: 2026-10-30 First seen: 2026-10-30 Status: active

Attack Surface

Low Complexity No Interaction Integ. Impact

CVSS Vector Breakdown

AV: Local

AC: Low

PR: Low

UI: None

S: Unchanged

C: None

I: High

A: High

Description

In the Linux kernel, the following vulnerability has been resolved: cifs: fix loff_t underflow in cifs_remap_file_range() when len == 0 With len == 0 (clone to EOF), the effective length is computed as: len = src_inode->i_size - off; If off > i_size, this is a negative loff_t, corrupting the ByteCount in the FSCTL_DUPLICATE_EXTENTS_TO_FILE request and inverting the range in filemap_write_and_wait_range(). The existing off >= i_size check fires only after the ioctl has already been sent. Snapshot i_size_read() once for both the bounds check and the length calculation, eliminating the TOCTOU and 32-bit torn-read risk. Reject off > src_size with -EINVAL. Treat off == src_size as a no-op, consistent with __generic_remap_file_range_prep().

Affected Software (9)

Vendor	Product	Version
Linux	Linux	04b38d601239b4d9be641b412cf4b7456a041c67 < 2c6eede83b3de1268db92c7e49741761c954aa26
Linux	Linux	04b38d601239b4d9be641b412cf4b7456a041c67 < ce813e5eebf46851e872ce59bdc34dc5dd4e29a4
Linux	Linux	04b38d601239b4d9be641b412cf4b7456a041c67 < f3d1ae1e6bc4a9f559185b6e7bd2b6375ec2fdd4
Linux	Linux	04b38d601239b4d9be641b412cf4b7456a041c67 < 7f62817fe049b0f3652518c1ba72631ec1e0a322
Linux	Linux	04b38d601239b4d9be641b412cf4b7456a041c67 < b098f5e5858797827666e6cd73033f52fc39b5f6
Linux	Linux	04b38d601239b4d9be641b412cf4b7456a041c67 < c2a0dcb5a7a1516aa6eb6d5cedca6a8e76527028
Linux	Linux	04b38d601239b4d9be641b412cf4b7456a041c67 < b057ca17b656345d04669cb87f2aff9b31d873db
Linux	Linux	04b38d601239b4d9be641b412cf4b7456a041c67 < 6c322f5cf7476ded7a9a20f7be72462065a03c68
Linux	Linux	4.5