# CVE-2026-90153: linux: In the Linux kernel, the following vulnerability has been resolved:  ksmbd: bound smb_check_perm_dacl() ACE walks by...

CVE-2026-90153 is fixed in 2 products on 1 platform, first by DEBIAN-CVE-2026-90153, released September 23, 2026. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2026-90153
- Priority: High
- CVSS: 8.1 (high)
- EPSS: 0.0052
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Sep 17, 2026

## Description

In the Linux kernel, the following vulnerability has been resolved:  ksmbd: bound smb_check_perm_dacl() ACE walks by DACL size  smb_check_perm_dacl() validates that the DACL fits inside the NT security descriptor, but then bounds its two ACE walks by the remaining NTSD length (acl_size) rather than the DACL's declared size (pdacl_size).  When pdacl->size is smaller than the trailing NTSD buffer, bytes after the declared DACL boundary - still inside the stored security descriptor - are parsed as ACEs during access checks.  A crafted DACL can place an access-granting ACE beyond pdacl->size, and the current code accepts it during SMB2_CREATE access validation, while parse_dacl() and smb_inherit_dacl() stop at pdacl_size.  Bound both ACE walks by pdacl_size to match the DACL boundary semantics used elsewhere in the server.  Validation: - semantic KUnit harness shows the post-boundary ACE is selected   before the fix and rejected (EACCES) after it - linux master (7.2-rc6), x86_64

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 13.5 (trixie) | 6.12.111-1 | [DEBIAN-CVE-2026-90153](https://patchblox.com/security/data/fix/linux/debian-cve-2026-90153.md) | Sep 23, 2026 |
| Linux | linux Debian 14 | 7.2.6-1 | [DEBIAN-CVE-2026-90153](https://patchblox.com/security/data/fix/linux/debian-cve-2026-90153.md) | Sep 23, 2026 |
| Linux | linux-6.12 Debian 12.15 (bookworm) | 6.12.111-1~deb12u1 | [DEBIAN-CVE-2026-90153](https://patchblox.com/security/data/fix/linux/debian-cve-2026-90153.md) | Sep 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 Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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