CVE-2026-31738

Denial of service via malformed ND options

Published May 1, 2026 · Updated May 1, 2026

Out-of-bounds access in Linux Kernel VXLAN code allows local users to interrupt the system through malformed IPv6 ND options. The vxlan_na_create() parser trusts option-provided lengths while advancing through the Neighbor Solicitation option span and can read a source LLADDR payload shorter than an Ethernet address. A low-privileged local user must deliver crafted options to affected VXLAN code; exploitation interrupts availability without reported data disclosure or modification.

CVSS severity5.5
Medium
EPSS probability0.12%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Out-of-bounds access in Linux Kernel VXLAN code allows local users to interrupt the system through malformed IPv6 ND options. The vxlan_na_create() parser trusts option-provided lengths while advancing through the Neighbor Solicitation option span and can read a source LLADDR payload shorter than an Ethernet address. A low-privileged local user must deliver crafted options to affected VXLAN code; exploitation interrupts availability without reported data disclosure or modification.

The record

CVE
CVE-2026-31738
Published
May 1, 2026
Updated
May 1, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. May 1, 2026CVE publishedPublication date reported by the CVE source.
  2. May 1, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=3.14
  2. Affected versionversion=3927dace523706cc00f808520eaf2125dd7c07b5
  3. Affected versionversion=4b29dba9c085a4fb79058fb1c45a2f6257ca3dfa <2029712fb2c87e9a8c75094906f2ee29bf08c500
  4. Affected versionversion=4b29dba9c085a4fb79058fb1c45a2f6257ca3dfa <602596c69a70e50d9ab8c6ae0290a01f88229dd7
  5. Affected versionversion=4b29dba9c085a4fb79058fb1c45a2f6257ca3dfa <901c1dd3bab2955d7e664f914c374c8c3ac2b958
  6. Affected versionversion=4b29dba9c085a4fb79058fb1c45a2f6257ca3dfa <afa9a05e6c4971bd5586f1b304e14d61fb3d9385
  7. Affected versionversion=4b29dba9c085a4fb79058fb1c45a2f6257ca3dfa <b69c4236255bd8de16cd876e58c6f0867d1d78b1
  8. Affected versionversion=4b29dba9c085a4fb79058fb1c45a2f6257ca3dfa <de20d2e3b9179d132f5f5b44e490d7c916c6321b
  9. Affected versionversion=4b29dba9c085a4fb79058fb1c45a2f6257ca3dfa <e476745917a1e288eb15e7ff49d286a86a4861d3
  10. Affected versionversion=4b29dba9c085a4fb79058fb1c45a2f6257ca3dfa <eddfce70a6f3107d1679b0c2fcbeb96b593bd679
  11. Affected versionversion=d8be18c52dbc94989f6d74637b731af39cd3d902

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=3.14; version=3927dace523706cc00f808520eaf2125dd7c07b5; version=4b29dba9c085a4fb79058fb1c45a2f6257ca3dfa <2029712fb2c87e9a8c75094906f2ee29bf08c500; version=4b29dba9c085a4fb79058fb1c45a2f6257ca3dfa <602596c69a70e50d9ab8c6ae0290a01f88229dd7; version=4b29dba9c085a4fb79058fb1c45a2f6257ca3dfa <901c1dd3bab2955d7e664f914c374c8c3ac2b958; version=4b29dba9c085a4fb79058fb1c45a2f6257ca3dfa <afa9a05e6c4971bd5586f1b304e14d61fb3d9385; version=4b29dba9c085a4fb79058fb1c45a2f6257ca3dfa <b69c4236255bd8de16cd876e58c6f0867d1d78b1; version=4b29dba9c085a4fb79058fb1c45a2f6257ca3dfa <de20d2e3b9179d132f5f5b44e490d7c916c6321b; version=4b29dba9c085a4fb79058fb1c45a2f6257ca3dfa <e476745917a1e288eb15e7ff49d286a86a4861d3; version=4b29dba9c085a4fb79058fb1c45a2f6257ca3dfa <eddfce70a6f3107d1679b0c2fcbeb96b593bd679; version=d8be18c52dbc94989f6d74637b731af39cd3d902

Published CVSS scores

5.5NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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