CVE-2026-46137Network attack vector

Unspecified impact via unlocked MPTCP timer callback

Published May 28, 2026 · Updated May 28, 2026

Data race in affected Linux Kernel releases allows attackers to cause unspecified impact via an MPTCP ADD_ADDR retransmission timer callback. The mptcp_pm_add_timer() callback runs in softirq context and accesses socket state without bh_lock_sock(), permitting concurrent socket use during retransmission processing. Reachability requires an MPTCP socket, an outstanding ADD_ADDR retransmission, and concurrent socket ownership; Linux has not published a concrete security consequence.

CVSS severity9.8
Critical
EPSS probability0.43%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Data race in affected Linux Kernel releases allows attackers to cause unspecified impact via an MPTCP ADD_ADDR retransmission timer callback. The mptcp_pm_add_timer() callback runs in softirq context and accesses socket state without bh_lock_sock(), permitting concurrent socket use during retransmission processing. Reachability requires an MPTCP socket, an outstanding ADD_ADDR retransmission, and concurrent socket ownership; Linux has not published a concrete security consequence.

The record

CVE
CVE-2026-46137
Published
May 28, 2026
Updated
May 28, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
CWE-362
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 28, 2026CVE publishedPublication date reported by the CVE source.
  2. May 28, 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=00cfd77b9063dcdf3628a7087faba60de85a9cc8 <013dcdc1961543b9a3433466bc8c79a2f4ca75b5
  2. Affected versionversion=00cfd77b9063dcdf3628a7087faba60de85a9cc8 <2ad56e434199ca24a812bb353667aa1c3860f513
  3. Affected versionversion=00cfd77b9063dcdf3628a7087faba60de85a9cc8 <5cd6e0ad79d2615264f63929f8b457ad97ae550d
  4. Affected versionversion=00cfd77b9063dcdf3628a7087faba60de85a9cc8 <6e4710d7d8782cb61af29a7e7111ddfc38b9e1a3
  5. Affected versionversion=00cfd77b9063dcdf3628a7087faba60de85a9cc8 <cc3c0399361efaaf7ae64262eb3f70829b1189c6
  6. Affected versionversion=5.10

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=00cfd77b9063dcdf3628a7087faba60de85a9cc8 <013dcdc1961543b9a3433466bc8c79a2f4ca75b5; version=00cfd77b9063dcdf3628a7087faba60de85a9cc8 <2ad56e434199ca24a812bb353667aa1c3860f513; version=00cfd77b9063dcdf3628a7087faba60de85a9cc8 <5cd6e0ad79d2615264f63929f8b457ad97ae550d; version=00cfd77b9063dcdf3628a7087faba60de85a9cc8 <6e4710d7d8782cb61af29a7e7111ddfc38b9e1a3; version=00cfd77b9063dcdf3628a7087faba60de85a9cc8 <cc3c0399361efaaf7ae64262eb3f70829b1189c6; version=5.10

Published CVSS scores

4.7Amazon LinuxCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H
9.8Linux kernel.org CNACVSS: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-362Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')

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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