CVE-2026-64318 partitions: aix: bound the pp_count scan to the ppe array
A crafted AIX partition table triggers an out-of-bounds read in the Linux kernel, potentially leaking memory or causing a crash.
- 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-2026-64318?
CVE-2026-64318 is a high-severity memory corruption vulnerability in Linux kernel, published on 25 Jul 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:
partitions: aix: bound the pp_count scan to the ppe array
aix_partition() reads the physical volume descriptor into a fixed-size struct pvd and then scans its physical-partition-extent array:
int numpps = be16_to_cpu(pvd->pp_count); ... for (i = 0; i < numpps; i += 1) { struct ppe *p = pvd->ppe + i; ... lp_ix = be16_to_cpu(p->lp_ix);
pvd points at a single kmalloc()'d struct pvd whose ppe[] member holds a fixed ARRAY_SIZE(pvd->ppe) (1016) entries, but the loop runs up to the on-disk pp_count. pp_count is an unvalidated __be16 read straight from the descriptor, so a crafted AIX image with pp_count larger than 1016 drives the loop to read pvd->ppe[i] past the end of the allocation (up to 65535 entries, ~2 MB out of bounds).
The partition scan runs without mounting anything, when a block device with a crafted AIX/IBM partition table appears (an attacker-supplied image attached with losetup -P, or a device auto-scanned by udev), via msdos_partition() -> aix_partition().
Clamp the scan to the number of entries the ppe[] array can hold.
Which versions are affected by CVE-2026-64318?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2026-64318?
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-2026-64318 being exploited?
There is no known exploitation of CVE-2026-64318 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as AZL-93713, BELL-CVE-2026-64318, DEBIAN-CVE-2026-64318, GHSA-499p-p84w-r6w8, ROOT-OS-DEBIAN-12-CVE-2026-64318, ROOT-OS-UBUNTU-2204-CVE-2026-64318 and 1 more.