What is CVE-2026-63867?

CVE-2026-63867 is a high-severity vulnerability in Linux. CVSS score: 8.2/10. Published 2026-07-19.

How severe is CVE-2026-63867?

High severity. CVSS v3 base score is 8.2 out of 10.

Vulnerability in Linux

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 t…

EPSS: 0.002 (5.6th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 8.2 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H.

Affected products

Linux — versions fa3fe2b150316b294f2c662653501273ff25bba8, 5.11, 0

References

416baaa9-dc9f-4396-8d5f-8c081fb06d67
416baaa9-dc9f-4396-8d5f-8c081fb06d67
416baaa9-dc9f-4396-8d5f-8c081fb06d67
416baaa9-dc9f-4396-8d5f-8c081fb06d67
416baaa9-dc9f-4396-8d5f-8c081fb06d67
416baaa9-dc9f-4396-8d5f-8c081fb06d67
416baaa9-dc9f-4396-8d5f-8c081fb06d67

Frequently asked questions

What is CVE-2026-63867?: CVE-2026-63867 is a high-severity vulnerability in Linux. CVSS score: 8.2/10. Published 2026-07-19.
How severe is CVE-2026-63867?: High severity. CVSS v3 base score is 8.2 out of 10.