ntfs: take invalidate_lock in ntfs_filemap_page_mkwrite()
- Exploited
- No known exploitation
- Fix
- No fix listed
- Who is exposed
- Not reported
Do first: Workaround: The checked facts do not describe a workaround. Until a fixed kernel is installed, the facts provide no specific steps to limit the affected code path.
- Last modified
- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean? →
- Published
- Whether CISA lists it in its Known Exploited Vulnerabilities catalog: proof that attackers are using it.What do these mean? →
- Not listed in CISA KEV
- A 0-100 score for how much a CVE matters across the industry: exploitation, exposure, how widely the software is used, severity and whether a fix exists.What do these mean? →
- 25/100 · provisional
- How many real-world setups can hit the bug, from the vendor's advisory and CISA data. It does not know your setup.What do these mean? →
- Unclear
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
Summary
In the Linux kernel, the following vulnerability has been resolved: ntfs: take invalidate_lock in ntfs_filemap_page_mkwrite() ntfs_filemap_page_mkwrite() calls iomap_page_mkwrite() without holding mapping->invalidate_lock, so a concurrent truncate or fallocate can be in the middle of invalidating pagecache and rewriting the runlist while the write fault maps blocks and dirties the folio. This races with ntfs_attr_fallocate(), which merges clusters into the in-memory runlist, drops the runlist lock, and only afterwards zeroes the newly allocated clusters on disk; and with the punch-hole/insert/collapse paths that free clusters after truncating the cache. Per Documentation/filesystems/locking.rst, ->page_mkwrite() must ensure there are no truncate/invalidate races, "usually mapping->invalidate_lock is suitable for proper serialization". xfs takes its mmaplock (= the invalidate_lock rwsem) shared in exactly this path. Take invalidate_lock shared around iomap_page_mkwrite(). The read-only fault path is already covered because filemap_fault() itself grabs invalidate_lock shared on instantiation/read paths; only page_mkwrite was bypassing it in this driver.
What to do
Workaround: The checked facts do not describe a workaround. Until a fixed kernel is installed, the facts provide no specific steps to limit the affected code path.
Timeline
- CVE published
- First seen by cve.now
Affected versions
- Linux Linux
Version range not reported
- Linux Linux
7.1
Evidence 2
- Link
- Link
Corrections
None so far.
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Questions about CVE-2026-99241
What does this mean?
The bug is a race in the Linux kernel's NTFS driver. It can occur when a truncate or fallocate runs on the same file while a write page fault is being handled. The fix takes the invalidate_lock in ntfs_filemap_page_mkwrite() to close that race. The checked facts do not state the resulting impact.Source: git.kernel.org
Am I affected, and how do I check?
The checked facts list Linux kernel as the product but give no affected version ranges. The setup involves NTFS files that receive write page faults while a truncate or fallocate runs on the same file. Compare your kernel version with the version list in the advisory to check your own system.Source: git.kernel.org
What should I do about it?
The checked facts do not name a fixed kernel version. The change to apply is the commit titled 'ntfs: take invalidate_lock in ntfs_filemap_page_mkwrite()'. Check the kernel advisory or the stable branch for the version that includes it.Source: git.kernel.org
Is it being exploited?
It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.Source: cve.now feed data
What if there's no patch?
The checked facts do not describe a workaround. Until a fixed kernel is installed, the facts provide no specific steps to limit the affected code path.Source: git.kernel.org