Linux Kernel up to 7.2.5 ksmbd check_lock_range locking

CVSS Meta Temp Score
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CTI Interest Score
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9.5$0-$5k0.00

Summaryinfo

A vulnerability, which was classified as very critical, has been found in Linux Kernel up to 6.1.187/6.6.156/6.12.109/6.18.51/7.2.5. The affected element is the function check_lock_range of the component ksmbd. This manipulation causes locking. This vulnerability is tracked as CVE-2026-90176. The attack is possible to be carried out remotely. No exploit exists. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability has been found in Linux Kernel up to 6.1.187/6.6.156/6.12.109/6.18.51/7.2.5 and classified as very critical. Affected by this vulnerability is the function check_lock_range of the component ksmbd. The manipulation with an unknown input leads to a locking vulnerability. The CWE definition for the vulnerability is CWE-667. The product does not properly acquire or release a lock on a resource, leading to unexpected resource state changes and behaviors. As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: ksmbd: Do not skip lock checks for single-byte ranges check_lock_range() uses inclusive ranges. Its callers pass the end offset as start + length - 1, so start == end represents a valid single-byte range rather than an empty range. The start == end shortcut therefore skips mandatory byte-range lock checks for one-byte reads, writes, copychunk operations and one-byte truncate ranges. A conflicting lock covering that byte is not checked and the operation is allowed to proceed. Remove the shortcut. The truncate size == inode->i_size case is already handled by only calling check_lock_range() when the new size differs from the current file size.

It is possible to read the advisory at git.kernel.org. This vulnerability is known as CVE-2026-90176 since 09/11/2026. The exploitation appears to be easy. The attack can be launched remotely. Technical details of the vulnerability are known, but there is no available exploit. The pricing for an exploit might be around USD $0-$5k at the moment (estimation calculated on 09/17/2026).

Upgrading to version 6.1.188, 6.6.157, 6.12.110, 6.18.52, 7.2.6 or 7.3-rc1 eliminates this vulnerability. Applying the patch a89cc145832e81c32199d4ca2e1ea8bd51ed601d/993e0158331d37c04da18efe551b5e1e35fb3078/f751d6e39d4c937c45f8fedc66699aa7d2d52288/84c2d8e807ac489f5c91769293fb15dfdae8bae8/07a9e289ff7edcc004f58952405f8a65c4e37512/d40c24634fe077a0dc91fd11fccf44ce12b454d5 is able to eliminate this problem. The best possible mitigation is suggested to be upgrading to the latest version.

Be aware that VulDB is the high quality source for vulnerability data.

Productinfo

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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

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

Exploitinginfo

Class: Locking
CWE: CWE-667
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 6.1.188/6.6.157/6.12.110/6.18.52/7.2.6/7.3-rc1
Patch: a89cc145832e81c32199d4ca2e1ea8bd51ed601d/993e0158331d37c04da18efe551b5e1e35fb3078/f751d6e39d4c937c45f8fedc66699aa7d2d52288/84c2d8e807ac489f5c91769293fb15dfdae8bae8/07a9e289ff7edcc004f58952405f8a65c4e37512/d40c24634fe077a0dc91fd11fccf44ce12b454d5

Timelineinfo

09/11/2026 CVE reserved
09/17/2026 +6 days Advisory disclosed
09/17/2026 +0 days VulDB entry created
09/17/2026 +0 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2026-90176 (🔒)
GCVE (CVE): GCVE-0-2026-90176
GCVE (VulDB): GCVE-100-406687

Entryinfo

Created: 09/17/2026 20:18
Changes: 09/17/2026 20:18 (59)
Complete: 🔍
Cache ID: 216::103

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