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.
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.
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | ||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Linux | Linux | unaffected |
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| Linux | Linux | affected |
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No data.
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Advisories
No advisories yet.
Fixes
Solution
No solution given by the vendor.
Workaround
No workaround given by the vendor.
References
History
Sun, 19 Jul 2026 14:45:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| 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. | |
| Title | mptcp: close TOCTOU race while computing rcv_wnd | |
| First Time appeared |
Linux
Linux linux Kernel |
|
| CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Linux
Linux linux Kernel |
|
| References |
|
|
Projects
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MITRE
Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2026-07-19T14:18:37.234Z
Reserved: 2026-07-19T07:54:57.017Z
Link: CVE-2026-63867
Vulnrichment
No data.
NVD
No data.
Redhat
No data.
OpenCVE Enrichment
No data.
Weaknesses
No weakness.