CVE-2026-89617 fs/ntfs3: validate dirty page table on log replay
A missing bounds check in the Linux kernel NTFS3 driver allows memory corruption during log replay, potentially leading to code execution or system crashes.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-89617?
CVE-2026-89617 is a high-severity memory corruption vulnerability in Linux, published on 11 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
fs/ntfs3: validate dirty page table on log replay
Each DIR_PAGE_ENTRY ends in a page_lcns[] array whose length is the on-disk lcns_follow field. check_rstbl() validates the table bookkeeping but never checks that this array fits in the entry, so a crafted lcns_follow lets the v0->v1 conversion memmove and later replay passes run off the entry.
Add check_dp_table() to reject, right after check_rstbl(), any entry larger than its size claims via struct_size() (the same expression used to allocate these entries, so the check is overflow-safe by construction). All consumers can then trust lcns_follow as the real capacity. This covers every page_lcns[] access whose index is bounded by the entry itself (the conversion memmove, the HotFix store via find_dp(), and the self-bounded scan loops). Accesses whose index comes from the log record need a separate bound and are handled in a follow-up patch.
Which versions are affected by CVE-2026-89617?
How do I fix CVE-2026-89617?
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-2026-89617 being exploited?
There is no known exploitation of CVE-2026-89617 in the wild and no public exploit code.
Sources
Also known as AZL-100271, BELL-CVE-2026-89617, DEBIAN-CVE-2026-89617, GHSA-gfmm-7qwj-299m, UBUNTU-CVE-2026-89617.