UNKNOWN NVD
CVE-2026-89640
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 t
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().
References
- https://git.kernel.org/stable/c/6c322f5cf7476ded7a9a20f7be72462065a03c68
- https://git.kernel.org/stable/c/b057ca17b656345d04669cb87f2aff9b31d873db
- https://git.kernel.org/stable/c/b098f5e5858797827666e6cd73033f52fc39b5f6
- https://git.kernel.org/stable/c/c2a0dcb5a7a1516aa6eb6d5cedca6a8e76527028
This unknown severity vulnerability was published on 2026-09-11 via NVD.
vulnfeed aggregates 13138 vulnerabilities from NVD, CISA KEV,
Ubuntu, Debian, Red Hat, Kubernetes, Exploit-DB, OSS-Security, GitHub and OpenStack — updated every 4 hours.