CVE-2026-31678

Kernel memory corruption via tunnel teardown race

Published Apr 25, 2026 · Updated Apr 25, 2026

Use-after-free in Linux Kernel Open vSwitch allows local users to corrupt kernel memory through concurrent tunnel-vport teardown. ovs_netdev_tunnel_destroy() drops the vport->dev netdev reference after NETDEV_UNREGISTER while RCU readers can still dereference it. CAP_NET_ADMIN in an unprivileged user namespace is sufficient to race vport deletion against readers, enabling kernel memory disclosure, kernel-state modification, or a crash.

CVSS severity7.8
High
EPSS probability0.10%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Use-after-free in Linux Kernel Open vSwitch allows local users to corrupt kernel memory through concurrent tunnel-vport teardown. ovs_netdev_tunnel_destroy() drops the vport->dev netdev reference after NETDEV_UNREGISTER while RCU readers can still dereference it. CAP_NET_ADMIN in an unprivileged user namespace is sufficient to race vport deletion against readers, enabling kernel memory disclosure, kernel-state modification, or a crash.

The record

CVE
CVE-2026-31678
Published
Apr 25, 2026
Updated
Apr 25, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
CWE-367, T1068
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=4.3
  2. Affected versionversion=a9020fde67a6eb77f8130feff633189f99264db1 <42f0d3d81209654c08ffdde5a34b9b92d2645896
  3. Affected versionversion=a9020fde67a6eb77f8130feff633189f99264db1 <6931d21f87bc6d657f145798fad0bf077b82486c
  4. Affected versionversion=a9020fde67a6eb77f8130feff633189f99264db1 <98b726ab5e2a4811e27c28e4d041f75bba147eab
  5. Affected versionversion=a9020fde67a6eb77f8130feff633189f99264db1 <9d56aced21fb9c104e8a3f3be9b21fbafe448ffc
  6. Affected versionversion=a9020fde67a6eb77f8130feff633189f99264db1 <b8c56a3fc5d879c0928f207a756b0f067f06c6a8
  7. Affected versionversion=a9020fde67a6eb77f8130feff633189f99264db1 <bbe7bd722bfaea36aab3da6cc60fb4a05c644643

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=4.3; version=a9020fde67a6eb77f8130feff633189f99264db1 <42f0d3d81209654c08ffdde5a34b9b92d2645896; version=a9020fde67a6eb77f8130feff633189f99264db1 <6931d21f87bc6d657f145798fad0bf077b82486c; version=a9020fde67a6eb77f8130feff633189f99264db1 <98b726ab5e2a4811e27c28e4d041f75bba147eab; version=a9020fde67a6eb77f8130feff633189f99264db1 <9d56aced21fb9c104e8a3f3be9b21fbafe448ffc; version=a9020fde67a6eb77f8130feff633189f99264db1 <b8c56a3fc5d879c0928f207a756b0f067f06c6a8; version=a9020fde67a6eb77f8130feff633189f99264db1 <bbe7bd722bfaea36aab3da6cc60fb4a05c644643

Published CVSS scores

7.8kernel.orgCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
5.5Oracle LinuxCVSS: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.

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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

CWE-367Time-of-check Time-of-use (TOCTOU) Race Condition
T1068Exploitation for Privilege Escalation

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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