CVE-2026-64216 netfs: Fix potential UAF in netfs_unlock_abandoned_read_pages()
A use-after-free vulnerability in the Linux kernel netfs subsystem allows attackers to potentially execute arbitrary code or escalate privileges.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-64216?
CVE-2026-64216 is a critical use after free vulnerability in Linux kernel, published on 24 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
netfs: Fix potential UAF in netfs_unlock_abandoned_read_pages()
netfs_unlock_abandoned_read_pages(rreq) accesses the index of the folios it is wanting to unlock and compares that to rreq->no_unlock_folio so that it doesn't unlock a folio being read for netfs_perform_write() or netfs_write_begin().
However, given that netfs_unlock_abandoned_read_pages() is called _after_ NETFS_RREQ_IN_PROGRESS is cleared, the one folio that it's not allowed to dereference is the one specified by ->no_unlock_folio as ownership immediately reverts to the caller.
Fix this by storing the folio pointer instead and using that rather than the index. Also fix netfs_unlock_read_folio() where the same applies.
Weakness: CWE-416
Which versions are affected by CVE-2026-64216?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2026-64216?
Apply the vendor's patch.
Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.
Is CVE-2026-64216 being exploited?
There is no known exploitation of CVE-2026-64216 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as BELL-CVE-2026-64216, DEBIAN-CVE-2026-64216, GHSA-wm9r-84gr-484q, ROOT-OS-DEBIAN-13-CVE-2026-64216, ROOT-OS-UBUNTU-2204-CVE-2026-64216, UBUNTU-CVE-2026-64216.