CVE-2026-64318

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.

Affected Software

References

• https://git.kernel.org/stable/c/09861651617ba0fec089e8b9477439e68398c110
• https://git.kernel.org/stable/c/2dc0bfd2fe355fb930de63c2f2eb8ced8570c579
• https://git.kernel.org/stable/c/44f37ee92fdcd377c41bdf6a31cdd8cc7d4c410e
• https://git.kernel.org/stable/c/4671bb74bba05fdd4acf670a35758c29e8c97b83
• https://git.kernel.org/stable/c/5eacdb1967378f5e5591cd27a2d8cdee2df1a599
• https://git.kernel.org/stable/c/b5e9c09309e18fd9839ad007c238120353ca0cc4
• https://git.kernel.org/stable/c/ce93228e2193a17d2c58b656e439bb39fe5c3af8
• https://git.kernel.org/stable/c/fd94a779020f2ecc8b2607f4c20b34acb1763b9a