CVE-2026-90418

Published Sep 17, 2026

Description

In the Linux kernel, the following vulnerability has been resolved: nilfs2: fix BUG in nilfs_copy_dirty_pages() on dirty state mismatch Syzbot reported a kernel BUG triggered within nilfs_copy_dirty_pages(), which copies dirty DAT file folios/pages to its shadow page cache. The BUG occurs when a retrieved dirty folio/page unexpectedly loses its 'dirty' status. This issue arises because, since the commit referenced below, the 'dirty' flag of a folio/page can be cleared asynchronously after the filesystem detects metadata corruption and transitions to read-only mode. Resolve the issue by returning an -EROFS error if the filesystem has transitioned to read-only mode. Also change the behavior to issue a kernel warning only once instead of triggering a kernel BUG when this unexpected 'dirty' state is detected while the filesystem is not in read-only mode.

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References

Frequently Asked Questions

What is CVE-2026-90418? +
In the Linux kernel, the following vulnerability has been resolved: nilfs2: fix BUG in nilfs_copy_dirty_pages() on dirty state mismatch Syzbot reported a kernel BUG triggered within nilfs_copy_dirty_pages(), which copies dirty DAT file folios/pages to its shadow page cache. The BUG occurs when a retrieved dirty folio/page unexpectedly loses its 'dirty' status. This issue arises because, since the commit referenced below, the 'dirty' flag of a folio/page can be cleared asynchronously after the filesystem detects metadata corruption and transitions to read-only mode. Resolve the issue by returning an -EROFS error if the filesystem has transitioned to read-only mode. Also change the behavior to issue a kernel warning only once instead of triggering a kernel BUG when this unexpected 'dirty' state is detected while the filesystem is not in read-only mode.
How do I check if I'm vulnerable to CVE-2026-90418? +
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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