Answer in brief
CVE-2026-63867 records a Unknown severity vulnerability in mptcp: close TOCTOU race while computing rcv_wnd. The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
Answer in brief
CVE-2026-63867 records a Unknown severity vulnerability in mptcp: close TOCTOU race while computing rcv_wnd. The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
A CVSS score is not reported in the current record. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | >=fa3fe2b150316b294f2c662653501273ff25bba8 <301a33fd590c408a05c5df800e0cc1e6a8a2f8f8 || >=fa3fe2b150316b294f2c662653501273ff25bba8 <68364963e5baf03f16b4420292291f75c8f66497 || >=fa3fe2b150316b294f2c662653501273ff25bba8 <907ac6b1658e0277f979fcdfae2a753b495c1510 || >=fa3fe2b150316b294f2c662653501273ff25bba8 <c4f4cf60797974873dbc8e100144682a6f2f861f || >=fa3fe2b150316b294f2c662653501273ff25bba8 <3b8cbba7c0ed31189c89f90be247b8973ffa79ef || >=fa3fe2b150316b294f2c662653501273ff25bba8 <8f4f0a157e8436a05bf8c3670b24dbc258911c43 || >=fa3fe2b150316b294f2c662653501273ff25bba8 <8ab24fdebc369c0dfb90f82c1650b1e66662bb45 | 301a33fd590c408a05c5df800e0cc1e6a8a2f8f8, 68364963e5baf03f16b4420292291f75c8f66497, 907ac6b1658e0277f979fcdfae2a753b495c1510, c4f4cf60797974873dbc8e100144682a6f2f861f, 3b8cbba7c0ed31189c89f90be247b8973ffa79ef, 8f4f0a157e8436a05bf8c3670b24dbc258911c43, 8ab24fdebc369c0dfb90f82c1650b1e66662bb45 |
| Linux/Linuxgeneric | 5.11 | Not reported |
Published upstream
Jul 19, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Aug 5, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Aug 5, 2026
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.
Quoted source text, attributed separately from HOL analysis.
A CVSS score is not reported in the current record. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | >=fa3fe2b150316b294f2c662653501273ff25bba8 <301a33fd590c408a05c5df800e0cc1e6a8a2f8f8 || >=fa3fe2b150316b294f2c662653501273ff25bba8 <68364963e5baf03f16b4420292291f75c8f66497 || >=fa3fe2b150316b294f2c662653501273ff25bba8 <907ac6b1658e0277f979fcdfae2a753b495c1510 || >=fa3fe2b150316b294f2c662653501273ff25bba8 <c4f4cf60797974873dbc8e100144682a6f2f861f || >=fa3fe2b150316b294f2c662653501273ff25bba8 <3b8cbba7c0ed31189c89f90be247b8973ffa79ef || >=fa3fe2b150316b294f2c662653501273ff25bba8 <8f4f0a157e8436a05bf8c3670b24dbc258911c43 || >=fa3fe2b150316b294f2c662653501273ff25bba8 <8ab24fdebc369c0dfb90f82c1650b1e66662bb45 | 301a33fd590c408a05c5df800e0cc1e6a8a2f8f8, 68364963e5baf03f16b4420292291f75c8f66497, 907ac6b1658e0277f979fcdfae2a753b495c1510, c4f4cf60797974873dbc8e100144682a6f2f861f, 3b8cbba7c0ed31189c89f90be247b8973ffa79ef, 8f4f0a157e8436a05bf8c3670b24dbc258911c43, 8ab24fdebc369c0dfb90f82c1650b1e66662bb45 |
| Linux/Linuxgeneric | 5.11 | Not reported |
Published upstream
Jul 19, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Aug 5, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Aug 5, 2026
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.
Quoted source text, attributed separately from HOL analysis.