# CVE-2026-64318: partitions: aix: bound the pp_count scan to the ppe array

CVE-2026-64318 is fixed in 2 products on 1 platform, first by DEBIAN-CVE-2026-64318, released July 26, 2026. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2026-64318
- Priority: High
- CVSS: 7.1 (Moderate)
- EPSS: 0.0016
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Jul 25, 2026
- Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-64318

## 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.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 12.15 (bookworm) | 6.1.180-1 | [DEBIAN-CVE-2026-64318](https://patchblox.com/security/data/fix/linux/debian-cve-2026-64318.md) | Jul 26, 2026 |
| Linux | linux Debian 13.5 (trixie) | 6.12.96-1 | [DEBIAN-CVE-2026-64318](https://patchblox.com/security/data/fix/linux/debian-cve-2026-64318.md) | Jul 26, 2026 |
| Linux | linux Debian 14 | 7.1.4-1 | [DEBIAN-CVE-2026-64318](https://patchblox.com/security/data/fix/linux/debian-cve-2026-64318.md) | Jul 26, 2026 |
| Linux | linux-6.12 Debian 12.15 (bookworm) | 6.12.100-1~deb12u1 | [DEBIAN-CVE-2026-64318](https://patchblox.com/security/data/fix/linux/debian-cve-2026-64318.md) | Jul 26, 2026 |

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Data as of 2026-11-09T07:25:28Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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