smb: client: use kzalloc to zero-initialize security descriptor buffer
Key facts
- Attack vector
- Local
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Denial of service
- Confidentiality · integrity · availability
- None · None · High
- Fix status
- Partial Red Hat: 3 without a fix
Attack profile from CVSS 3.1 · NVD. Fix status from CNA and Red Hat. Impact type from CWE-908 and the CVSS impact.
Summary
In the Linux kernel, the following vulnerability has been resolved: smb: client: use kzalloc to zero-initialize security descriptor buffer Commit 62e7dd0a39c2d ("smb: common: change the data type of num_aces to le16") split struct smb_acl's __le32 num_aces field into __le16 num_aces and __le16 reserved. The reserved field corresponds to Sbz2 in the MS-DTYP ACL wire format, which must be zero [1]. When building an ACL descriptor in build_sec_desc(), we are using a kmalloc()'ed descriptor buffer and writing the fields explicitly using le16() writes now. This never writes to the 2 byte reserved field, leaving it as uninitialized heap data. When the reserved field happens to contain non-zero slab garbage, Samba rejects the security descriptor with "ndr_pull_security_descriptor failed: Range Error", causing chmod to fail with EINVAL. Change kmalloc() to kzalloc() to ensure the entire buffer is zero-initialized. [1] https://learn.microsoft.com/en-us/openspecs/windows_protocols/ms-dtyp/20233ed8-a6c6-4097-aafa-dd545ed24428
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| Linux | Linux | 6.12.23 to before 6.12.88; 6.13.11 to before 6.14 | 6.12.88, 6.14 | Patch available | CNA |
| Linux | Linux | 6.14 and later | 6.12.88, 6.18.30, 7.0.7, 7.1 | Patch available | CNA |
- Linux VendorLinux Affected 6.12.23 to before 6.12.88; 6.13.11 to before 6.14 Fixed in 6.12.88, 6.14 Patch available CNA
- Linux VendorLinux Affected 6.14 and later Fixed in 6.12.88, 6.18.30, 7.0.7, 7.1 Patch available CNA
CPE configurations NVD · 6
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | 6.12.23 to before 6.12.88; 6.13.11 to before 6.14; 6.14.1 to before 6.18.30; 6.19 to before 7.0.7 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:6.14:-:*:*:*:*:*:* | 6.14 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:6.14:rc6:*:*:*:*:*:* | 6.14 rc6 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:6.14:rc7:*:*:*:*:*:* | 6.14 rc7 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:7.1:rc1:*:*:*:*:*:* | 7.1 rc1 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:7.1:rc2:*:*:*:*:*:* | 7.1 rc2 | Vulnerable | Linux |
- cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* Versions 6.12.23 to before 6.12.88; 6.13.11 to before 6.14; 6.14.1 to before 6.18.30; 6.19 to before 7.0.7 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:6.14:-:*:*:*:*:*:* Versions 6.14 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:6.14:rc6:*:*:*:*:*:* Versions 6.14 rc6 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:6.14:rc7:*:*:*:*:*:* Versions 6.14 rc7 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:7.1:rc1:*:*:*:*:*:* Versions 7.1 rc1 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:7.1:rc2:*:*:*:*:*:* Versions 7.1 rc2 Vulnerable ·Linux
Remediation
- Fix · CNA Linux (Linux) Fixed in 6.12.88, 6.14
- Fix · CNA Linux (Linux) Fixed in 6.12.88, 6.18.30, 7.0.7, 7.1
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 10 | Affected | No fix yet |
| Red Hat Enterprise Linux 8 | Affected | No fix yet |
| Red Hat Enterprise Linux 9 | Affected | No fix yet |
Not affected: 3 products
- Red Hat Enterprise Linux 6
- Red Hat Enterprise Linux 7
- Red Hat Enterprise Linux 9
Timeline
- 2026-10-02 Threatist record created from CVE-2026-46139
- 2026-10-03 Alias added: GHSA-v8jf-78w3-v9hm
- 2026-10-29 Affected versions changed · Red Hat
- 2026-11-06 CISA SSVC decision points changed
References
Patch 5
- https://git.kernel.org/stable/c/4c3ed344a970aad51388ac3b0145b98318f0e21f
- https://git.kernel.org/stable/c/941a1e6eb35440336913afc88a82103291956d5d
- https://git.kernel.org/stable/c/be1ef9512a3f5a755895c24f31b334342f4aa15b
- https://git.kernel.org/stable/c/9bdb2ca31368b7671949dfb94a5d57ffccd01edd
- https://git.kernel.org/stable/c/5e489c6c47a2ac15edbaca153b9348e42c1eacab
More Linux Kernel vulnerabilities
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- TI-2013-05264 The (1) get_user and (2) put_user API functions in the Linux kernel before 3.5.5 on the… KEVCVSS 3.1HIGH 8.8
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- TI-2013-01864 The perf_swevent_init function in kernel/events/core.c in the Linux kernel before 3.8.9… KEVCVSS 3.1HIGH 8.4
- TI-2021-05514 Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACE KEVCVSS 3.1HIGH 8.3
Sources
- CVE-2026-46139 · CVE Program
- CVE-2026-46139 · NVD
- FIRST EPSS
- GHSA-v8jf-78w3-v9hm · GitHub Advisory Database · CC BY 4.0
- CVE-2026-46139 · Red Hat security data · CC BY 4.0
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