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CVE-2026-31706
Description
A flaw was found in ksmbd, a Linux kernel module that provides an in-kernel SMB server. An authenticated client can exploit this vulnerability by manipulating the num_aces value within the parent directory's security.NTACL extended attribute. This manipulation causes ksmbd to attempt an excessively large heap allocation, which can lead to a Denial of Service (DoS) by exhausting available memory resources.
- Bugzilla 2464413: kernel: ksmbd: validate num_aces and harden ACE walk in smb_inherit_dacl()
- CWE-1284: Improper Validation of Specified Quantity in Input
Frequently Asked Questions
For open source software shipped by multiple vendors, the CVSS base scores may vary for each vendor's version depending on the version they ship, how they ship it, the platform, and even how the software is compiled. This makes scoring of vulnerabilities difficult for third-party vulnerability databases such as NVD that only provide a single CVSS base score for each vulnerability. Red Hat scores reflect how a vulnerability affects our products specifically.
For more information, see https://access.redhat.com/solutions/762393.
For more information, see https://access.redhat.com/solutions/762393.
- "Under investigation" doesn't necessarily mean that the product is affected by this vulnerability. It only means that our Analysis Team is still working on determining whether the product is affected and how it is affected.
- The term 'Affected' means that our Analysis team has determined that this product, such as Red Hat Enterprise Linux 8 or OpenShift Container Platform 4, is affected by this vulnerability and a fix may be released to address this issue in the near future. This includes all minor releases of this product unless noted otherwise in the Statement text.
A "will not fix" status means that a fix for an affected product version is not planned or not possible due to complexity, which may create additional risk.
Available options depend mostly on the Impact of the vulnerability and the current Life Cycle phase of your product. Overall, you have the following options:
Available options depend mostly on the Impact of the vulnerability and the current Life Cycle phase of your product. Overall, you have the following options:
- Upgrade to a supported product version that includes a fix for this vulnerability (recommended).
- Apply a mitigation (if one exists).
- Customers with the Technical Account Manager (TAM) RHEL Security Select Add-on can review this CVE directly with their TAM.
A deferred status means that a fix for an affected product version is not guaranteed due to higher-priority development work.
Available options depend mostly on the Impact of the vulnerability and the current Life Cycle phase of your product. Overall, you have the following options:
Available options depend mostly on the Impact of the vulnerability and the current Life Cycle phase of your product. Overall, you have the following options:
- Apply a mitigation (if one exists).
- Red Hat Engineering focuses on addressing high-priority issues based on the impact and product lifecycle expectations. Therefore, lower-priority issues will not receive immediate fixes.
- Customers with the technical account manager (TAM) RHEL Security Select Add-on can review this CVE directly with their TAM.
A mitigation is an action that can be taken to reduce the impact of a security vulnerability, without deploying any fixes.
The listed products were found to include one or more of the components that this vulnerability affects. These products underwent a thorough evaluation to determine their affectedness by this vulnerability. Note that layered products (such as container-based offerings) that consume affected components from any of the products listed in this table may be affected and are not represented.
In order to maintain code stability and compatibility, Red Hat usually does not rebase packages to entirely new versions. Instead, we backport fixes and new features to an older version of the package we distribute. This can result in some security scanners that only consider the package version to report the package as vulnerable. To avoid this, we suggest that you use an approved vulnerability scanner from our Red Hat Vulnerability Scanner Certification program.
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