CVE-2026-31669Network attack vector

Kernel memory corruption via unsafe MPTCP slab allocation

Published Apr 24, 2026 · Updated Apr 24, 2026

Use-after-free in Linux Kernel MPTCP IPv6 subflows allows remote attackers to corrupt kernel memory during concurrent ehash lookups. mptcp_subflow_init copies tcpv6_prot before its slab is registered, leaving tcpv6_prot_override.slab NULL and allocating child sockets from a cache without SLAB_TYPESAFE_BY_RCU. Exploitation requires enabled MPTCP and an IPv6 child subflow freed during a lockless lookup; immediate reuse permits kernel-level data access, code execution, or service interruption.

CVSS severity9.8
Critical
EPSS probability0.46%
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 MPTCP IPv6 subflows allows remote attackers to corrupt kernel memory during concurrent ehash lookups. mptcp_subflow_init copies tcpv6_prot before its slab is registered, leaving tcpv6_prot_override.slab NULL and allocating child sockets from a cache without SLAB_TYPESAFE_BY_RCU. Exploitation requires enabled MPTCP and an IPv6 child subflow freed during a lockless lookup; immediate reuse permits kernel-level data access, code execution, or service interruption.

The record

CVE
CVE-2026-31669
Published
Apr 24, 2026
Updated
Apr 24, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
CWE-416
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 24, 2026CVE publishedPublication date reported by the CVE source.
  2. Apr 24, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

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

  1. Affected versionversion=5.12
  2. Affected versionversion=b19bc2945b40b9fd38e835700907ffe8534ef0de <15fa9ead4d5e6b6b9c794e84144146c917f2cb62
  3. Affected versionversion=b19bc2945b40b9fd38e835700907ffe8534ef0de <3fd6547f5b8ac99687be6d937a0321efda760597
  4. Affected versionversion=b19bc2945b40b9fd38e835700907ffe8534ef0de <9b55b253907e7431210483519c5ad711a37dafa1
  5. Affected versionversion=b19bc2945b40b9fd38e835700907ffe8534ef0de <b313e9037d98c13938740e5ebda7852929366dff
  6. Affected versionversion=b19bc2945b40b9fd38e835700907ffe8534ef0de <eb9c6aeb512f877cf397deb1e4526f646c70e4a7
  7. Affected versionversion=b19bc2945b40b9fd38e835700907ffe8534ef0de <f6e1f25fa5e733570f6d6fe37a4dfed2a0deba47
  8. Affected versionversion=b19bc2945b40b9fd38e835700907ffe8534ef0de <fb1f54b7d16f393b8b65d328410f78b4beea8fcc

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=5.12; version=b19bc2945b40b9fd38e835700907ffe8534ef0de <15fa9ead4d5e6b6b9c794e84144146c917f2cb62; version=b19bc2945b40b9fd38e835700907ffe8534ef0de <3fd6547f5b8ac99687be6d937a0321efda760597; version=b19bc2945b40b9fd38e835700907ffe8534ef0de <9b55b253907e7431210483519c5ad711a37dafa1; version=b19bc2945b40b9fd38e835700907ffe8534ef0de <b313e9037d98c13938740e5ebda7852929366dff; version=b19bc2945b40b9fd38e835700907ffe8534ef0de <eb9c6aeb512f877cf397deb1e4526f646c70e4a7; version=b19bc2945b40b9fd38e835700907ffe8534ef0de <f6e1f25fa5e733570f6d6fe37a4dfed2a0deba47; version=b19bc2945b40b9fd38e835700907ffe8534ef0de <fb1f54b7d16f393b8b65d328410f78b4beea8fcc

Published CVSS scores

9.8kernel.orgCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/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)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-416Use After Free

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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