CVE-2026-89710 NFSv4.1: fix layout segment leak on the pnfs_layout_process() forget path
A memory leak in the Linux kernel's NFSv4.1 implementation allows remote attackers to cause a denial of service by exhausting kernel memory.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-89710?
CVE-2026-89710 is a memory corruption vulnerability in Linux, published on 11 Sep 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:
NFSv4.1: fix layout segment leak on the pnfs_layout_process() forget path
When the server returns a new layout stateid while a valid one is still held, pnfs_layout_process() calls pnfs_mark_matching_lsegs_return() on the on-stack free_me list and jumps to out_forget. Segments whose reference count drops to zero are unlinked from lo->plh_segs and moved to free_me by mark_lseg_invalid(); for an idle cached segment the layout header holds the only reference, so this happens on the first decrement.
out_forget never drains free_me -- only the success path calls pnfs_free_lseg_list().
Commit 814b84971388 ("pNFS/NFSv4: Fix a layout segment leak in pnfs_layout_process()") added the drain; commit 08bd8dbe8882 ("pNFS/NFSv4: Try to return invalid layout in pnfs_layout_process()") removed it while switching the destination to lo->plh_return_segs, which is drained elsewhere. Commit fb700ef02676 ("NFSv4.1: Simplify layout return in pnfs_layout_process()") switched the destination back to free_me without restoring the drain.
Restore the pnfs_free_lseg_list() call.
Which versions are affected by CVE-2026-89710?
How do I fix CVE-2026-89710?
Apply the vendor's patch.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2026-89710 being exploited?
There is no known exploitation of CVE-2026-89710 in the wild and no public exploit code.
Sources
Also known as AZL-100508, BELL-CVE-2026-89710, DEBIAN-CVE-2026-89710, GHSA-84pc-7mxq-h2j8, UBUNTU-CVE-2026-89710.