CVE Catalog

CVE-2026-98126

Unknown
Published: Translated: NVD NIST

Summary

In the Linux kernel SMB client, smb3_zero_range() may extend a file's EOF without checking RLIMIT_FSIZE when FALLOC_FL_ZERO_RANGE is used without FALLOC_FL_KEEP_SIZE. The fix calls inode_newsize_ok() before sending the zero-range request when the operation would extend EOF.

Risk Assessment

A local user can bypass their own file-size limit (ulimit -f) and create a file larger than allowed on a CIFS mount, potentially exhausting disk space or violating quota policies.

Recommendation

Update the Linux kernel to a version containing the fix for this issue (smb/client: validate new EOF for zero range).

Other vulnerabilities in Linux kernel

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Original NVD description (English source)

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.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS