# CVE-2026-40706: ntfs-3g: In NTFS-3G 2022.10.3 before 2026.2.25, a heap buffer overflow exists in ntfs_build_permissions_posix() in acls.c that...

CVE-2026-40706 is fixed in 4 products on 1 platform, first by libntfs-3g89t64 1:2022.10.3-5ubuntu1, released April 21, 2026. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2026-40706
- Priority: High
- CVSS: 8.4 (high)
- EPSS: 0.0017
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Apr 21, 2026

## Description

In NTFS-3G 2022.10.3 before 2026.2.25, a heap buffer overflow exists in ntfs_build_permissions_posix() in acls.c that allows an attacker to corrupt heap memory in the SUID-root ntfs-3g binary by crafting a malicious NTFS image. The overflow is triggered on the READ path (stat, readdir, open) when processing a security descriptor with multiple ACCESS_DENIED ACEs containing WRITE_OWNER from distinct group SIDs.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | libntfs-3g89 Ubuntu 22.04.1 LTS (jammy) | 1:2021.8.22-3ubuntu1.3 | [libntfs-3g89 1:2021.8.22-3ubuntu1.3](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-libntfs-3g89-1-2021.8.22-3ubuntu1.3.md) | Apr 30, 2026 |
| Linux | libntfs-3g89t64 Ubuntu 24.04.5 LTS (noble) | 1:2022.10.3-1.2ubuntu3.1 | [libntfs-3g89t64 1:2022.10.3-1.2ubuntu3.1](https://patchblox.com/security/data/fix/linux/ubuntu-noble-libntfs-3g89t64-1-2022.10.3-1.2ubuntu3.1.md) | Apr 30, 2026 |
| Linux | libntfs-3g89t64 Ubuntu 25.10 (questing) | 1:2022.10.3-5ubuntu0.25.10.1 | [libntfs-3g89t64 1:2022.10.3-5ubuntu0.25.10.1](https://patchblox.com/security/data/fix/linux/ubuntu-questing-libntfs-3g89t64-1-2022.10.3-5ubuntu0.25.10.1.md) | Apr 30, 2026 |
| Linux | libntfs-3g89t64 Ubuntu 26.04.1 LTS (resolute) | 1:2022.10.3-5ubuntu1 | [libntfs-3g89t64 1:2022.10.3-5ubuntu1](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-libntfs-3g89t64-1-2022.10.3-5ubuntu1.md) | Apr 21, 2026 |
| Linux | ntfs-3g Debian 12.15 (bookworm) | 1:2022.10.3-1+deb12u3 | [DEBIAN-CVE-2026-40706](https://patchblox.com/security/data/fix/linux/debian-cve-2026-40706.md) | May 15, 2026 |
| Linux | ntfs-3g Debian 13.5 (trixie) | 1:2022.10.3-5+deb13u1 | [DEBIAN-CVE-2026-40706](https://patchblox.com/security/data/fix/linux/debian-cve-2026-40706.md) | May 15, 2026 |
| Linux | ntfs-3g Debian 14 | 1:2026.2.25-1 | [DEBIAN-CVE-2026-40706](https://patchblox.com/security/data/fix/linux/debian-cve-2026-40706.md) | May 15, 2026 |
| Linux | ntfs-3g Ubuntu 22.04.1 LTS (jammy) | 1:2021.8.22-3ubuntu1.3 | [ntfs-3g 1:2021.8.22-3ubuntu1.3](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-ntfs-3g-1-2021.8.22-3ubuntu1.3.md) | Apr 30, 2026 |
| Linux | ntfs-3g Ubuntu 24.04.5 LTS (noble) | 1:2022.10.3-1.2ubuntu3.1 | [ntfs-3g 1:2022.10.3-1.2ubuntu3.1](https://patchblox.com/security/data/fix/linux/ubuntu-noble-ntfs-3g-1-2022.10.3-1.2ubuntu3.1.md) | Apr 30, 2026 |
| Linux | ntfs-3g Ubuntu 25.10 (questing) | 1:2022.10.3-5ubuntu0.25.10.1 | [ntfs-3g 1:2022.10.3-5ubuntu0.25.10.1](https://patchblox.com/security/data/fix/linux/ubuntu-questing-ntfs-3g-1-2022.10.3-5ubuntu0.25.10.1.md) | Apr 30, 2026 |
| Linux | ntfs-3g Ubuntu 26.04.1 LTS (resolute) | 1:2022.10.3-5ubuntu1 | [ntfs-3g 1:2022.10.3-5ubuntu1](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-ntfs-3g-1-2022.10.3-5ubuntu1.md) | Apr 21, 2026 |
| Linux | ntfs-3g_ntfsprogs sles 15.6 | 2022.5.17-150000.3.24.1 | [SUSE-SU-2026:1571-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-1571-1.md) | Apr 23, 2026 |
| Linux | ntfs-3g_ntfsprogs sles 15.7 | 2022.5.17-150000.3.24.1 | [SUSE-SU-2026:1571-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-1571-1.md) | Apr 23, 2026 |

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Data as of 2026-11-08T06:59:42Z 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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