# CVE-2026-52992: fs/adfs: validate nzones in adfs_validate_bblk()

CVE-2026-52992 is fixed in linux on 1 platform, first by DEBIAN-CVE-2026-52992, released June 25, 2026. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2026-52992
- Priority: High
- CVSS: 7.8 (Moderate)
- EPSS: 0.0018
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Jun 24, 2026
- Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-52992

## Description

In the Linux kernel, the following vulnerability has been resolved:  fs/adfs: validate nzones in adfs_validate_bblk()  Reject ADFS disc records with a zero zone count during boot block validation, before the disc record is used.  When nzones is 0, adfs_read_map() passes it to kmalloc_array(0, ...) which returns ZERO_SIZE_PTR, and adfs_map_layout() then writes to dm[-1], causing an out-of-bounds write before the allocated buffer.  adfs_validate_dr0() already rejects nzones != 1 for old-format images.  Add the equivalent check to adfs_validate_bblk() for new-format images so that a crafted image with nzones == 0 is rejected at probe time.  Found by syzkaller.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 12.15 (bookworm) | 6.1.176-1 | [DEBIAN-CVE-2026-52992](https://patchblox.com/security/data/fix/linux/debian-cve-2026-52992.md) | Jun 25, 2026 |
| Linux | linux Debian 13.5 (trixie) | 6.12.94-1 | [DEBIAN-CVE-2026-52992](https://patchblox.com/security/data/fix/linux/debian-cve-2026-52992.md) | Jun 25, 2026 |
| Linux | linux Debian 14 | 7.0.10-1 | [DEBIAN-CVE-2026-52992](https://patchblox.com/security/data/fix/linux/debian-cve-2026-52992.md) | Jun 25, 2026 |

---

Data as of 2026-11-09T01:18:40Z 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 Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

Free to use with attribution: show "Data: Patchblox Patch Radar" with a link to https://patchblox.com/security/patch-radar. Terms, including what needs a written agreement: https://patchblox.com/security/patch-radar/use-the-data

Product names, logos and trademarks shown on Patch Radar belong to their respective owners. They are used only to identify the software each security fix applies to and to help readers find their platform. Their use does not imply any affiliation with, or endorsement by, those owners, and Patchblox is not affiliated with any of them.