mptcp: close TOCTOU race while computing rcv_wnd
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.
CVE-2026-63867
Primary source · Revision 1
Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.
Security context
Source reference: cve:CVE-2026-63867
Linux
Source reference: /containers/cna/affected/0/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Linux
Source reference: /containers/cna/affected/1/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Structured affected-version data
Original package identities and version rules from this source.
[
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "fa3fe2b150316b294f2c662653501273ff25bba8",
"lessThan": "301a33fd590c408a05c5df800e0cc1e6a8a2f8f8",
"versionType": "git"
},
{
"status": "affected",
"version": "fa3fe2b150316b294f2c662653501273ff25bba8",
"lessThan": "68364963e5baf03f16b4420292291f75c8f66497",
"versionType": "git"
},
{
"status": "affected",
"version": "fa3fe2b150316b294f2c662653501273ff25bba8",
"lessThan": "907ac6b1658e0277f979fcdfae2a753b495c1510",
"versionType": "git"
},
{
"status": "affected",
"version": "fa3fe2b150316b294f2c662653501273ff25bba8",
"lessThan": "c4f4cf60797974873dbc8e100144682a6f2f861f",
"versionType": "git"
},
{
"status": "affected",
"version": "fa3fe2b150316b294f2c662653501273ff25bba8",
"lessThan": "3b8cbba7c0ed31189c89f90be247b8973ffa79ef",
"versionType": "git"
},
{
"status": "affected",
"version": "fa3fe2b150316b294f2c662653501273ff25bba8",
"lessThan": "8f4f0a157e8436a05bf8c3670b24dbc258911c43",
"versionType": "git"
},
{
"status": "affected",
"version": "fa3fe2b150316b294f2c662653501273ff25bba8",
"lessThan": "8ab24fdebc369c0dfb90f82c1650b1e66662bb45",
"versionType": "git"
}
],
"programFiles": [
"net/mptcp/options.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "5.11"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "5.11",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "5.15.210",
"versionType": "semver",
"lessThanOrEqual": "5.15.*"
},
{
"status": "unaffected",
"version": "6.1.176",
"versionType": "semver",
"lessThanOrEqual": "6.1.*"
},
{
"status": "unaffected",
"version": "6.6.143",
"versionType": "semver",
"lessThanOrEqual": "6.6.*"
},
{
"status": "unaffected",
"version": "6.12.94",
"versionType": "semver",
"lessThanOrEqual": "6.12.*"
},
{
"status": "unaffected",
"version": "6.18.36",
"versionType": "semver",
"lessThanOrEqual": "6.18.*"
},
{
"status": "unaffected",
"version": "7.0.13",
"versionType": "semver",
"lessThanOrEqual": "7.0.*"
},
{
"status": "unaffected",
"version": "7.1",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"net/mptcp/options.c"
],
"defaultStatus": "affected"
}
]- Related CVEs
- CVE-2026-63867
Source reference:
/cveMetadata/cveId
Publisher severity
high
Source reference: /containers/cna/metrics
- Event
- #40874 · Revision 1
- Added to Heist Feed
- Publisher date