Linux Kernel up to 6.12.110/6.18.52 smb/client buffer overflow

CVSS Meta Temp Score
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CTI Interest Score
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4.4$0-$5k0.00+

Summaryinfo

A vulnerability marked as problematic has been reported in Linux Kernel up to 6.12.110/6.18.52. This vulnerability affects unknown code of the component smb/client. The manipulation leads to buffer overflow. This vulnerability is documented as CVE-2026-93794. The attack can be initiated remotely. There is not any exploit available. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability, which was classified as problematic, has been found in Linux Kernel up to 6.12.110/6.18.52. This issue affects an unknown code of the component smb/client. The manipulation with an unknown input leads to a buffer overflow vulnerability. Using CWE to declare the problem leads to CWE-120. The product copies an input buffer to an output buffer without verifying that the size of the input buffer is less than the size of the output buffer, leading to a buffer overflow. Impacted is integrity, and availability. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: smb/client: flush dirty data before punching a hole Punching a hole after a large buffered write may leave the range reported as data. Reproduce it with: xfs_io -f \ -c "pwrite -b 3m -S 0x61 0 3m" \ -c "fpunch 1m 1m" \ -c "seek -h 0" \ -c "seek -d 1m" \ /mnt/test/repro Punching 1 MiB at offset 1 MiB should produce: 0 1 MiB 2 MiB 3 MiB | DATA | HOLE | DATA | EOF Instead, the entire file is reported as data. SEEK_HOLE(0) returns EOF, and SEEK_DATA(1M) returns 1M. This happens because a dirty folio spanning the punched range can be written back after the punch and refill the hole. Fix this by flushing and waiting for dirty data in the punched range before invalidating the page cache and issuing FSCTL_SET_ZERO_DATA. The xfstests generic/539 pass against Samba/ksmbd with this change.

It is possible to read the advisory at git.kernel.org. The identification of this vulnerability is CVE-2026-93794 since 09/18/2026. The exploitation is known to be easy. The attack may be initiated remotely. It demands that the victim is doing some kind of user interaction. The technical details are unknown and an exploit is not publicly available. The pricing for an exploit might be around USD $0-$5k at the moment (estimation calculated on 09/24/2026).

Upgrading to version 6.12.111 or 6.18.53 eliminates this vulnerability. Applying the patch 6c265aca08155e519a8f6f6071c59dff4f535f70/39562a56cdb515f6635c3e7bfe6629439b18a169/d7d2adcd022baade5cab65ca492ce63421ce3a6e is able to eliminate this problem. The best possible mitigation is suggested to be upgrading to the latest version.

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Productinfo

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CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 4.6
VulDB Meta Temp Score: 4.4

VulDB Base Score: 4.6
VulDB Temp Score: 4.4
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

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

Exploitinginfo

Class: Buffer overflow
CWE: CWE-120 / CWE-119
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

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

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Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 6.12.111/6.18.53
Patch: 6c265aca08155e519a8f6f6071c59dff4f535f70/39562a56cdb515f6635c3e7bfe6629439b18a169/d7d2adcd022baade5cab65ca492ce63421ce3a6e

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-2026-93794 (🔒)
GCVE (CVE): GCVE-0-2026-93794
GCVE (VulDB): GCVE-100-409511

Entryinfo

Created: 09/24/2026 18:54
Changes: 09/24/2026 18:54 (58)
Complete: 🔍
Cache ID: 216::103

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