CVE-2026-31738
Analyzed Analyzed - Analysis Complete
VXLAN ND Option Length Validation Flaw in Linux Kernel

Publication date: 2026-05-01

Last updated on: 2026-05-07

Assigner: kernel.org

Description
In the Linux kernel, the following vulnerability has been resolved: vxlan: validate ND option lengths in vxlan_na_create vxlan_na_create() walks ND options according to option-provided lengths. A malformed option can make the parser advance beyond the computed option span or use a too-short source LLADDR option payload. Validate option lengths against the remaining NS option area before advancing, and only read source LLADDR when the option is large enough for an Ethernet address.
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Meta Information
Published
2026-05-01
Last Modified
2026-05-07
Generated
2026-06-16
AI Q&A
2026-05-01
EPSS Evaluated
2026-06-14
NVD
CVE-2026-31738
EUVD
EUVD-2026-26551
Affected Vendors & Products
Showing 17 associated CPEs
Vendor Product Version / Range
linux linux_kernel 3.14
linux linux_kernel 3.14
linux linux_kernel 7.0
linux linux_kernel 7.0
linux linux_kernel 7.0
linux linux_kernel 7.0
linux linux_kernel 7.0
linux linux_kernel 7.0
linux linux_kernel From 5.11 (inc) to 5.15.203 (exc)
linux linux_kernel From 6.13 (inc) to 6.18.22 (exc)
linux linux_kernel From 3.14.1 (inc) to 5.10.253 (exc)
linux linux_kernel From 5.16 (inc) to 6.1.168 (exc)
linux linux_kernel From 6.19 (inc) to 6.19.12 (exc)
linux linux_kernel From 6.7 (inc) to 6.12.81 (exc)
linux linux_kernel From 6.2 (inc) to 6.6.134 (exc)
linux linux_kernel From 3.12.18 (inc) to 3.13 (exc)
linux linux_kernel From 3.13.10 (inc) to 3.14 (exc)
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Exploitability
CWE
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KEV
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CWE ID Description
CWE-UNKNOWN
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Impact Analysis

This vulnerability in the Linux kernel's vxlan_na_create function involves improper validation of Neighbor Discovery (ND) option lengths. A malformed option can cause the parser to read beyond the intended option span or use an incorrectly sized source link-layer address payload. This could potentially lead to unexpected behavior or memory corruption within the kernel's network processing.

Executive Summary

This vulnerability exists in the Linux kernel's vxlan component, specifically in the function vxlan_na_create. The function processes Neighbor Discovery (ND) options based on lengths provided by those options. However, if an option is malformed, the parser can either advance beyond the intended option span or use a source LLADDR option payload that is too short.

The fix involves validating the lengths of these options against the remaining Neighbor Solicitation (NS) option area before advancing the parser, and ensuring that the source LLADDR is only read when the option is large enough to contain a full Ethernet address.

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