Description
In the Linux kernel, the following vulnerability has been resolved: smb/client: validate new EOF for zero range When FALLOC_FL_ZERO_RANGE is used without FALLOC_FL_KEEP_SIZE, smb3_zero_range() may extend EOF without checking RLIMIT_FSIZE, allowing the file to grow beyond the caller's file-size limit. Fix this by calling inode_newsize_ok() before sending the zero-range request when the operation would extend EOF. Reproducer, using a file on a CIFS mount: bash -c ' FILE=/mnt/cifs/repro trap "" SIGXFSZ ulimit -f 3072 truncate -s 2M "$FILE" fallocate --zero-range -o 0 -l 4M "$FILE" echo "fallocate rc=$?" stat -c "file size=%s" "$FILE" ' Before this change, the operation succeeds despite the 3 MiB limit: fallocate rc=0 file size=4194304 After this change, fallocate fails and leaves the file at 2 MiB.
Affected products
linux: linux kernel
References5
- git.kernel.org/stable/c/06a4f9049cb6dc319bceec2dc813ba89add8b828 Patch
- git.kernel.org/stable/c/3673f057b64abfa957e8ae84448db69369a5091a Patch
- git.kernel.org/stable/c/5fbd8848f2e25c8163896ec52863df2305a3bb63 Patch
- git.kernel.org/stable/c/88972e35750792e717af287dc71f42a03b5cbce4 Patch
- git.kernel.org/stable/c/f320ca20c273a26cd779bdb2b2e4b076a95c76f6 Patch
Metrics
- CVSS 3.1
-
5.5
MEDIUM
Score source: NVD
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H - EPSS — exploit probability
- 0% percentile: 2 · as of 9 November 2026
- CWE
- CWE-770
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