Strix
26.1K

CVE-2026-63867

HIGHCVSS 8.2/10EPSS 0.32%

Last modified

CVE-2026-63867 is a high-severity vulnerability rated 8.2/10 on the CVSS scale. In the Linux kernel, the following vulnerability has been resolved: mptcp: close TOCTOU race while computing rcv_wnd The MPTCP output path access locklessly the MPTCP-level ack_seq in multiple times, using possibly different values for the data_ack in the DSS option and to compute the announced rcv wnd for the same packet. Refactor the cote to avoid inconsistencies which may confuse the peer. Also ensure that the MPTCP level rcv wnd is updated only when the egress packet actually contains a DSS ack.. EPSS estimates a 0.32% chance of exploitation in the next 30 days.

Description

In the Linux kernel, the following vulnerability has been resolved: mptcp: close TOCTOU race while computing rcv_wnd The MPTCP output path access locklessly the MPTCP-level ack_seq in multiple times, using possibly different values for the data_ack in the DSS option and to compute the announced rcv wnd for the same packet. Refactor the cote to avoid inconsistencies which may confuse the peer. Also ensure that the MPTCP level rcv wnd is updated only when the egress packet actually contains a DSS ack.

Metrics

CVSS 3.1
8.2/10

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

EPSS Probability
0.32%

24.5th percentile

Probability of exploitation in the next 30 days. Learn more

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

VendorProductVersions
LinuxLinux>= fa3fe2b150316b294f2c662653501273ff25bba8, < 301a33fd590c408a05c5df800e0cc1e6a8a2f8f8; >= fa3fe2b150316b294f2c662653501273ff25bba8, < 68364963e5baf03f16b4420292291f75c8f66497; >= fa3fe2b150316b294f2c662653501273ff25bba8, < 907ac6b1658e0277f979fcdfae2a753b495c1510; >= fa3fe2b150316b294f2c662653501273ff25bba8, < c4f4cf60797974873dbc8e100144682a6f2f861f; >= fa3fe2b150316b294f2c662653501273ff25bba8, < 3b8cbba7c0ed31189c89f90be247b8973ffa79ef; >= fa3fe2b150316b294f2c662653501273ff25bba8, < 8f4f0a157e8436a05bf8c3670b24dbc258911c43; >= fa3fe2b150316b294f2c662653501273ff25bba8, < 8ab24fdebc369c0dfb90f82c1650b1e66662bb45
LinuxLinux5.11

References

Timeline

Published
Last Modified
Status
Awaiting Analysis

Frequently Asked Questions

What is CVE-2026-63867?
In the Linux kernel, the following vulnerability has been resolved: mptcp: close TOCTOU race while computing rcv_wnd The MPTCP output path access locklessly the MPTCP-level ack_seq in multiple times, using possibly different values for the data_ack in the DSS option and to compute the announced rcv wnd for the same packet. Refactor the cote to avoid inconsistencies which may confuse the peer. Also ensure that the MPTCP level rcv wnd is updated only when the egress packet actually contains a DSS ack.
How severe is CVE-2026-63867?
CVE-2026-63867 has a CVSS score of 8.2/10 (HIGH severity). The EPSS model estimates a 0.32% probability of exploitation in the next 30 days.
How do I fix CVE-2026-63867?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

How Strix Helps

Related CVEs from 2026

View all 2026CVEs →

Are you affected by CVE-2026-63867?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST