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Linux KernelOperating system · Linux

CVE-2026-46137

CRITICAL · 9.8 CVSS v3.1 Published 2026-05-28
Fix available
A fix is available. Upgrade to 5.10.259 / 5.15.210 or later.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable No privileges Zero-click Patch available

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
In the Linux kernel, the following vulnerability has been resolved: mptcp: pm: ADD_ADDR rtx: fix potential data-race This mptcp_pm_add_timer() helper is executed as a timer callback in softirq context. To avoid any data races, the socket lock needs to be held with bh_lock_sock(). If the socket is in use, retry again soon after, similar to what is done with the keepalive timer.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · moderate confidence

A data race vulnerability exists in the Linux kernel's MPTCP (MultiPath TCP) path manager where the mptcp_pm_add_timer() callback runs in softirq context without properly holding the socket lock via bh_lock_sock(). This can lead to race conditions when the ADD_ADDR retransmission timer fires while the socket is in active use.

MitigationApply the kernel patch that ensures bh_lock_sock() is held in the timer callback to serialize access, or update to a kernel version containing the fix. Given the CVSS 9.8 critical rating, prioritize patching systems running MPTCP.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Linux KernelOperating system
Affected:>= 5.10, < 5.10.259>= 5.11, < 5.15.210>= 5.16, < 6.1.176>= 6.2, < 6.6.141>= 6.7, < 6.12.91>= 6.13, < 6.18.30>= 6.19, < 7.0.7= 7.1

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Check kernel version against affected ranges
    Run `uname -r` or `cat /proc/version` to get the running kernel version. Compare it to the affected ranges: >= 5.10, < 5.10.259; >= 5.11, < 5.15.210; >= 5.16, < 6.1.176; >= 6.2, < 6.6.141; >= 6.7, < 6.12.91; >= 6.13, < 6.18.30; >= 6.19, < 7.0.7; = 7.1
    Affected if The kernel version falls within any of the listed vulnerable ranges and MPTCP is in use
  2. Verify MPTCP kernel support is loaded or compiled in
    Check if the mptcp kernel module is loaded with `lsmod | grep mptcp` or check kernel config via `cat /boot/config-$(uname -r) | grep -i mptcp`
    Affected if MPTCP support exists in the kernel (module loaded or compiled in)
  3. Detect active MPTCP sockets on the system
    Query for MPTCP connections using `ss -m | grep mptcp` or `cat /proc/net/mptcp` to see if any MPTCP sockets are established
    Affected if Active MPTCP connections or sockets exist on the system
  4. Check for ADD_ADDR retransmission timer usage
    Inspect MPTCP path manager configuration via `cat /proc/sys/net/mptcp/` or monitor for mptcp_pm_add_timer activity in kernel tracing if available
    Affected if MPTCP path manager ADD_ADDR functionality is enabled and in use

The system is affected if it runs a vulnerable kernel version within the listed ranges AND has MPTCP enabled with active connections using the path manager ADD_ADDR feature.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 5.10.259 / 5.15.210 / 6.1.176 or later
Fixed in 5.10.2595.15.2106.1.176
Vendor patch git.kernel.org →
Interim mitigation

Apply the kernel patch that ensures bh_lock_sock() is held in the timer callback to serialize access, or update to a kernel version containing the fix. Given the CVSS 9.8 critical rating, prioritize patching systems running MPTCP.

Recommended fix High confidence

6.6.141 (or latest stable 6.6.x release)

  1. Upgrade the Linux kernel to version 5.10.259 or later for the 5.10.x branch
  2. OR upgrade to version 5.15.210 or later for the 5.11-5.15.x branch
  3. OR upgrade to version 6.1.176 or later for the 5.16-6.1.x branch
  4. OR upgrade to version 6.6.141 or later for the 6.2-6.6.x branch
  5. After kernel upgrade, reboot the system to load the patched kernel
  6. Alternatively, apply the upstream stable patch commit 013dcdc1961543b9a3433466bc8c79a2f4ca75b5 to the affected kernel source and rebuild
Caveat Standard kernel upgrade risks apply - verify driver compatibility with new kernel version

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Linux Kernel Scoped from the published advisory
  • Consultation2.0 h
  • Implementation3.0 h
  • Testing4.0 h
  • Review / QA2.0 h
11.0 hours of engineering $1,900
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-46137 in production — separate from our analysis above.

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What this is

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What belongs here
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  • Version or environment caveats, and links to real fixes
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