Linux Kernel up to 6.18.26/7.0.3/7.1-rc1 vmalloc vrealloc_node_align out-of-bounds

Summaryinfo

A vulnerability, which was classified as critical, has been found in Linux Kernel up to 6.18.26/7.0.3/7.1-rc1. Affected by this vulnerability is the function vrealloc_node_align of the component vmalloc. Performing a manipulation results in out-of-bounds. This vulnerability is reported as CVE-2026-46281. No exploit exists. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability, which was classified as problematic, was found in Linux Kernel up to 6.18.26/7.0.3/7.1-rc1. This affects the function vrealloc_node_align of the component vmalloc. The manipulation with an unknown input leads to a out-of-bounds vulnerability. CWE is classifying the issue as CWE-125. The product reads data past the end, or before the beginning, of the intended buffer. This is going to have an impact on confidentiality. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: vmalloc: fix buffer overflow in vrealloc_node_align() Commit 4c5d3365882d ("mm/vmalloc: allow to set node and align in vrealloc") added the ability to force a new allocation if the current pointer is on the wrong NUMA node, or if an alignment constraint is not met, even if the user is shrinking the allocation. On this path (need_realloc), the code allocates a new object of 'size' bytes and then memcpy()s 'old_size' bytes into it. If the request is to shrink the object (size < old_size), this results in an out-of-bounds write on the new buffer. Fix this by bounding the copy length by the new allocation size.

The advisory is shared at git.kernel.org. This vulnerability is uniquely identified as CVE-2026-46281 since 05/13/2026. 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 06/08/2026).

Upgrading to version 6.18.27, 7.0.4 or 7.1-rc2 eliminates this vulnerability. Applying the patch e9b057a44deff4c59c13f44672a5cc74dcd57522/b281adf71f786c325eb6d6d1582d4d05313438a8/82d1f01292d3f09bf063f829f8ab8de12b4280a1 is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. 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

• 6.18.0
• 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
• 7.0.0
• 7.0.1
• 7.0.2
• 7.0.3
• 7.1-rc1

License

• open-source

Website

• Vendor: https://www.kernel.org/

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