CVE-2026-99137

Published Oct 28, 2026

Description

In the Linux kernel, the following vulnerability has been resolved: cifs: don't update i_size in cifs_do_truncate without a cached handle If find_writable_file() returns null, cifs_file_flush will return 0 without issuing set_file_size, and the outer 'if (!rc)' block will set i_size to 0 before telling the server to truncate. If the cifs_open() then fails, the inode will have size 0, while the server file is unchanged. Move the netfs_resize_file() and cifs_setsize() into the 'if (cfile)', so they only run after a successful set_file_size. In the no-handle else branch, evict stale pages with truncate_inode_pages before the O_TRUNC open to dispose of old cache pages, and let the open response set the i_size.

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References

Frequently Asked Questions

What is CVE-2026-99137? +
In the Linux kernel, the following vulnerability has been resolved: cifs: don't update i_size in cifs_do_truncate without a cached handle If find_writable_file() returns null, cifs_file_flush will return 0 without issuing set_file_size, and the outer 'if (!rc)' block will set i_size to 0 before telling the server to truncate. If the cifs_open() then fails, the inode will have size 0, while the server file is unchanged. Move the netfs_resize_file() and cifs_setsize() into the 'if (cfile)', so they only run after a successful set_file_size. In the no-handle else branch, evict stale pages with truncate_inode_pages before the O_TRUNC open to dispose of old cache pages, and let the open response set the i_size.
How do I check if I'm vulnerable to CVE-2026-99137? +
You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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