CVE-2026-63867

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Source
https://cve.org/CVERecord?id=CVE-2026-63867
Import Source
https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-63867.json
JSON Data
https://api.osv.dev/v1/vulns/CVE-2026-63867
Downstream
Published
2026-07-19T14:18:37.234Z
Modified
2026-07-21T03:47:35.245350801Z
Severity
  • 8.2 (High) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H CVSS Calculator
Summary
mptcp: close TOCTOU race while computing rcv_wnd
Details

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 ackseq in multiple times, using possibly different values for the dataack 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.

Database specific 
{
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/63xxx/CVE-2026-63867.json",
    "cna_assigner": "Linux"
}
References

Affected packages

Git / git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git

Affected ranges

Type
GIT
Repo
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
Events
Introduced
fa3fe2b150316b294f2c662653501273ff25bba8
Fixed
301a33fd590c408a05c5df800e0cc1e6a8a2f8f8
Fixed
68364963e5baf03f16b4420292291f75c8f66497
Fixed
907ac6b1658e0277f979fcdfae2a753b495c1510
Fixed
c4f4cf60797974873dbc8e100144682a6f2f861f
Fixed
3b8cbba7c0ed31189c89f90be247b8973ffa79ef
Fixed
8f4f0a157e8436a05bf8c3670b24dbc258911c43
Fixed
8ab24fdebc369c0dfb90f82c1650b1e66662bb45

Database specific

source 
"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-63867.json"

Linux / Kernel

Package

Name
Kernel

Affected ranges

Type
ECOSYSTEM
Events
Introduced
5.11.0
Fixed
5.15.210
Type
ECOSYSTEM
Events
Introduced
5.16.0
Fixed
6.1.176
Type
ECOSYSTEM
Events
Introduced
6.2.0
Fixed
6.6.143
Type
ECOSYSTEM
Events
Introduced
6.7.0
Fixed
6.12.94
Type
ECOSYSTEM
Events
Introduced
6.13.0
Fixed
6.18.36
Type
ECOSYSTEM
Events
Introduced
6.19.0
Fixed
7.0.13

Database specific

source 
"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-63867.json"