CVE-2026-31679

Kernel memory exposure via malformed MPLS actions

Published Apr 25, 2026 · Updated Apr 25, 2026

Improper MPLS action validation in the Linux kernel Open vSwitch module allows local users to expose kernel memory or interrupt service. The validate_set() function accepts variable-length OVS_KEY_ATTR_MPLS data for SET and SET_MASKED actions although action handling reads a fixed-size struct ovs_key_mpls. Reaching the flaw requires low-privilege local access able to submit crafted Open vSwitch Netlink actions; the CNA does not specify whether interruption is a crash or hang.

CVSS severity7.1
High
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

Improper MPLS action validation in the Linux kernel Open vSwitch module allows local users to expose kernel memory or interrupt service. The validate_set() function accepts variable-length OVS_KEY_ATTR_MPLS data for SET and SET_MASKED actions although action handling reads a fixed-size struct ovs_key_mpls. Reaching the flaw requires low-privilege local access able to submit crafted Open vSwitch Netlink actions; the CNA does not specify whether interruption is a crash or hang.

The record

CVE
CVE-2026-31679
Published
Apr 25, 2026
Updated
Apr 25, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Apr 25, 2026CVE publishedPublication date reported by the CVE source.
  2. Apr 25, 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=5.5
  2. Affected versionversion=fbdcdd78da7c95f1b970d371e1b23cbd3aa990f3 <2ca33b88a79ca42f017ae0f7011280325655438e
  3. Affected versionversion=fbdcdd78da7c95f1b970d371e1b23cbd3aa990f3 <4cae986225f8b8679ad86b924918e7d75a96aa61
  4. Affected versionversion=fbdcdd78da7c95f1b970d371e1b23cbd3aa990f3 <546b68ac893595877ffbd7751e5c55fd1c43ede6
  5. Affected versionversion=fbdcdd78da7c95f1b970d371e1b23cbd3aa990f3 <68f32ef0683c8d1c05cd2e4f16818fa63ff59c6f
  6. Affected versionversion=fbdcdd78da7c95f1b970d371e1b23cbd3aa990f3 <8ed7b9930cbc3bc71f868fa79a68700ac88d586a
  7. Affected versionversion=fbdcdd78da7c95f1b970d371e1b23cbd3aa990f3 <98de18d327ef8cbbb704980e359e4872d8c28997
  8. Affected versionversion=fbdcdd78da7c95f1b970d371e1b23cbd3aa990f3 <bd50c7484c3bb34097571c1334174fb8b7408036
  9. Affected versionversion=fbdcdd78da7c95f1b970d371e1b23cbd3aa990f3 <c1f97152df8dfb17e855ddf0fc409b7bd13e9700

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=5.5; version=fbdcdd78da7c95f1b970d371e1b23cbd3aa990f3 <2ca33b88a79ca42f017ae0f7011280325655438e; version=fbdcdd78da7c95f1b970d371e1b23cbd3aa990f3 <4cae986225f8b8679ad86b924918e7d75a96aa61; version=fbdcdd78da7c95f1b970d371e1b23cbd3aa990f3 <546b68ac893595877ffbd7751e5c55fd1c43ede6; version=fbdcdd78da7c95f1b970d371e1b23cbd3aa990f3 <68f32ef0683c8d1c05cd2e4f16818fa63ff59c6f; version=fbdcdd78da7c95f1b970d371e1b23cbd3aa990f3 <8ed7b9930cbc3bc71f868fa79a68700ac88d586a; version=fbdcdd78da7c95f1b970d371e1b23cbd3aa990f3 <98de18d327ef8cbbb704980e359e4872d8c28997; version=fbdcdd78da7c95f1b970d371e1b23cbd3aa990f3 <bd50c7484c3bb34097571c1334174fb8b7408036; version=fbdcdd78da7c95f1b970d371e1b23cbd3aa990f3 <c1f97152df8dfb17e855ddf0fc409b7bd13e9700

Published CVSS scores

7.1Linux kernel CVE teamCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/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.

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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.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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