Linux Kernel up to 6.12.110/6.18.52 ksmbd ndr_decode_v4_ntacl memory leak

CVSS Meta Temp Score CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.	Current Exploit Price (≈) Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.	CTI Interest Score Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
9.5	$0-$5k	0.11+

Summaryinfo

A vulnerability identified as very critical has been detected in Linux Kernel up to 6.12.110/6.18.52. This affects the function ndr_decode_v4_ntacl of the component ksmbd. The manipulation leads to memory leak. This vulnerability is referenced as CVE-2026-93811. Remote exploitation of the attack is possible. No exploit is available. You should upgrade the affected component.

Detailsinfo

A vulnerability, which was classified as very critical, has been found in Linux Kernel up to 6.12.110/6.18.52. This issue affects the function ndr_decode_v4_ntacl of the component ksmbd. The manipulation with an unknown input leads to a memory leak vulnerability. Using CWE to declare the problem leads to CWE-401. The product does not sufficiently track and release allocated memory after it has been used, which slowly consumes remaining memory. Impacted is confidentiality, integrity, and availability. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: ksmbd: Fix acl.sd_buf memory leak and invalid sd_size error handling 1. When ndr_decode_v4_ntacl() fails, the code jumped to free_n_data which only freed n.data, skipping kfree(acl.sd_buf) and leaking the buffer. Zero-initialize struct xattr_ntacl acl, reorder error labels to out_free to release acl.sd_buf on all error paths. 2. if (acl.sd_size < sizeof(struct smb_ntsd)) is true, original code returned success without freeing sd_buf and left stale *pntsd. Set rc = -EINVAL before jumping to out_free to return error code and free buffer.

The advisory is shared at git.kernel.org. The identification of this vulnerability is CVE-2026-93811 since 09/18/2026. The exploitation is known to be easy. The attack may be initiated remotely. Technical details are known, but no exploit is available. The price for an exploit might be around USD $0-$5k at the moment (estimation calculated on 09/24/2026). MITRE ATT&CK project uses the attack technique T1499 for this issue.

Upgrading to version 6.12.111 or 6.18.53 eliminates this vulnerability. Applying the patch c3836f55e0dab96314774215e12d87f63fa919f2/6e6329322ad733c5b23555c609353841560b26bc/d708a36634bb7b6f94d0e76d587d2ec50b2b93b5 is able to eliminate this problem. The best possible mitigation is suggested to be upgrading to the latest version.

If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 6.12.110
• 6.18.0
• 6.18.1
• 6.18.2
• 6.18.3
• 6.18.4
• 6.18.5
• 6.18.6
• 6.18.7
• 6.18.8
• 6.18.9
• 6.18.10
• 6.18.11
• 6.18.12
• 6.18.13
• 6.18.14
• 6.18.15
• 6.18.16
• 6.18.17
• 6.18.18
• 6.18.19
• 6.18.20
• 6.18.21
• 6.18.22
• 6.18.23
• 6.18.24
• 6.18.25
• 6.18.26
• 6.18.27
• 6.18.28
• 6.18.29
• 6.18.30
• 6.18.31
• 6.18.32
• 6.18.33
• 6.18.34
• 6.18.35
• 6.18.36
• 6.18.37
• 6.18.38
• 6.18.39
• 6.18.40
• 6.18.41
• 6.18.42
• 6.18.43
• 6.18.44
• 6.18.45
• 6.18.46
• 6.18.47
• 6.18.48
• 6.18.49
• 6.18.50
• 6.18.51
• 6.18.52

License

• open-source

Website

• Vendor: https://www.kernel.org/

CPE 2.3info

• 🔒
• 🔒
• 🔒

CPE 2.2info

• 🔒
• 🔒
• 🔒

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 9.9
VulDB Meta Temp Score: 9.5

VulDB Base Score: 9.9
VulDB Temp Score: 9.5
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AV	AC	Au	C	I	A
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳

Vector	Complexity	Authentication	Confidentiality	Integrity	Availability
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock

VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Memory leak
CWE: CWE-401 / CWE-404
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

0-Day	Unlock	Unlock	Unlock	Unlock
Today	Unlock	Unlock	Unlock	Unlock

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 6.12.111/6.18.53
Patch: c3836f55e0dab96314774215e12d87f63fa919f2/6e6329322ad733c5b23555c609353841560b26bc/d708a36634bb7b6f94d0e76d587d2ec50b2b93b5

Timelineinfo

09/18/2026 CVE reserved
09/24/2026 +6 days Advisory disclosed
09/24/2026 +0 days VulDB entry created
09/24/2026 +0 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2026-93811 (🔒)
GCVE (CVE): GCVE-0-2026-93811
GCVE (VulDB): GCVE-100-409565

Entryinfo

Created: 09/24/2026 19:19
Changes: 09/24/2026 19:19 (59)
Complete: 🔍
Cache ID: 216::103

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Discussion

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