CVE-2026-90118 ntfs: fix off-by-one page overflow in ntfs_decompress()
An off-by-one error in the Linux kernel NTFS driver allows out-of-bounds writes when reading corrupted compressed data, potentially leading to code execution or crashes.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2026-90118?
CVE-2026-90118 is a high-severity memory corruption vulnerability in Linux, published on 17 Sep 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Official description
In the Linux kernel, the following vulnerability has been resolved:
ntfs: fix off-by-one page overflow in ntfs_decompress()
The per-token range check in ntfs_decompress() uses
if (cb >= cb_sb_end || dp_addr > dp_sb_end) break;
so dp_addr == dp_sb_end falls through to the symbol copy `*dp_addr++ = *cb++`, writing one byte past the destination page. Since NTFS_SB_SIZE == PAGE_SIZE the destination is a single page, so the byte lands in the adjacent page, and *dest_ofs is left one past the sub-block end (the later `*dest_ofs &= ~PAGE_MASK` then yields 1, not 0, so the page is never finalized and later sub-blocks keep writing further past it). A corrupted compressed $DATA attribute thus produces a bounded run of out-of-bounds writes when the file is read.
Break as soon as dp_addr reaches dp_sb_end; a full sub-block still completes, as its final copy advances dp_addr to exactly dp_sb_end.
Which versions are affected by CVE-2026-90118?
How do I fix CVE-2026-90118?
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-2026-90118 being exploited?
There is no known exploitation of CVE-2026-90118 in the wild and no public exploit code.
Sources
Also known as DEBIAN-CVE-2026-90118, GHSA-fvx8-6m5h-cx99, UBUNTU-CVE-2026-90118.