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Mallory
Medium

Out-of-bounds read in Linux kernel VXLAN vxlan_na_create

IdentifiersCVE-2026-31738CWE-125

CVE-2026-31738 is a Linux kernel vulnerability in the VXLAN subsystem, specifically in vxlan_na_create(), which parses IPv6 Neighbor Discovery (ND) options while constructing a Neighbor Advertisement. The function walks ND options using attacker-controlled option length fields. If a malformed ND option is supplied, the parser can advance beyond the computed ND option span or attempt to consume a source link-layer address (LLADDR) option whose payload is too short for an Ethernet address. The fix adds validation that each option length fits within the remaining Neighbor Solicitation option area before advancing the parser, and ensures the source LLADDR is only read when the option is large enough. Based on the available description, this is a bounds-checking failure leading to out-of-bounds memory access during ND option parsing in VXLAN.

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ANALYST BRIEF

Impact, mitigation & remediation

What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.

Impact

What an attacker gets, and what they’ve been doing with it.

Successful exploitation can cause the kernel to read beyond the intended ND option buffer boundaries or process undersized LLADDR data, which can destabilize the networking stack and lead to denial of service. Published scoring indicates the primary impact is availability, though SUSE also assigns confidentiality and integrity impact in its own scoring. The provided source material does not establish reliable evidence of code execution.

Mitigation

If you can’t patch tonight, do this now.

If immediate patching is not possible, reduce exposure by limiting local unprivileged access to systems that can reach or influence the vulnerable VXLAN/IPv6 Neighbor Discovery processing path, and disable or restrict unnecessary VXLAN usage where operationally feasible. Because the issue is in kernel packet parsing, there is no complete mitigation short of applying the fixed kernel.

Remediation

Patch, then assume compromise.

Apply a kernel update containing the vxlan_na_create() fix that validates ND option lengths against the remaining option area and verifies the source LLADDR option is large enough before reading it. SUSE indicates fixed packages are available across multiple product lines, including kernel-default 6.4.0-46.1 or later for SUSE Linux Micro 6.0/6.1, 6.12.0-160000.33.1 or later for SUSE Linux Micro 6.2/openSUSE Leap 16.0/SLES 16.0, and 6.4.0-150700.53.55.1 or later for SLES 15 SP7. Administrators should install the relevant vendor kernel update and reboot into the patched kernel.
PUBLIC EXPLOITS

Exploits

No public exploits tracked yet. Mallory keeps watching.

VALID 0 / 0 TOTALView more in app

No public exploit code observed for this vulnerability.

EXPOSURE SURFACE

Affected products & vendors

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VendorProductType
LinuxLinux Kerneloperating_system

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ACTIVITY FEED

Recent activity

4 sources tracked across advisories and community write-ups. News coverage will land here when it surfaces.

No news coverage yet. Advisories and community discussion only.

What this page doesn’t show

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Exposure mapping

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Threat actor evidence

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Associated malware

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Detection signatures

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Vendor-by-vendor mapping

Cross-references every affected SKU, including bundled OEM variants.

Social activity

Community discussion across Reddit, Mastodon, and other social sources.