Answer in brief
CVE-2026-45889 records a Medium severity (CVSS 5.5) vulnerability in mptcp: do not account for OoO in mptcp_rcvbuf_grow(). 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.
CVSS is 5.5. 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 | >=e118cdc34dd109562b64f6a397f68cd33b041d5b <fb7bf00b04a6b48859f52035d4e745848c2b4c79 || >=e118cdc34dd109562b64f6a397f68cd33b041d5b <400ee4854adef1e4983812a3decf6717ea020136 || >=e118cdc34dd109562b64f6a397f68cd33b041d5b <6b329393502e5857662b851a13f947209c588587 | fb7bf00b04a6b48859f52035d4e745848c2b4c79, 400ee4854adef1e4983812a3decf6717ea020136, 6b329393502e5857662b851a13f947209c588587 |
| Linux/Linuxgeneric | 6.18 | Not reported |
Published upstream
May 27, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Jun 25, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Jun 25, 2026
In the Linux kernel, the following vulnerability has been resolved: mptcp: do not account for OoO in mptcp_rcvbuf_grow() MPTCP-level OoOs are physiological when multiple subflows are active concurrently and will not cause retransmissions nor are caused by drops. Accounting for them in mptcp_rcvbuf_grow() causes the rcvbuf slowly drifting towards tcp_rmem[2]. Remove such accounting. Note that subflows will still account for TCP-level OoO when the MPTCP-level rcvbuf is propagated. This also closes a subtle and very unlikely race condition with rcvspace init; active sockets with user-space holding the msk-level socket lock, could complete such initialization in the receive callback, after that the first OoO data reaches the rcvbuf and potentially triggering a divide by zero Oops.
Quoted source text, attributed separately from HOL analysis.
Answer in brief
CVE-2026-45889 records a Medium severity (CVSS 5.5) vulnerability in mptcp: do not account for OoO in mptcp_rcvbuf_grow(). 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.
CVSS is 5.5. 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 | >=e118cdc34dd109562b64f6a397f68cd33b041d5b <fb7bf00b04a6b48859f52035d4e745848c2b4c79 || >=e118cdc34dd109562b64f6a397f68cd33b041d5b <400ee4854adef1e4983812a3decf6717ea020136 || >=e118cdc34dd109562b64f6a397f68cd33b041d5b <6b329393502e5857662b851a13f947209c588587 | fb7bf00b04a6b48859f52035d4e745848c2b4c79, 400ee4854adef1e4983812a3decf6717ea020136, 6b329393502e5857662b851a13f947209c588587 |
| Linux/Linuxgeneric | 6.18 | Not reported |
Published upstream
May 27, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Jun 25, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Jun 25, 2026
In the Linux kernel, the following vulnerability has been resolved: mptcp: do not account for OoO in mptcp_rcvbuf_grow() MPTCP-level OoOs are physiological when multiple subflows are active concurrently and will not cause retransmissions nor are caused by drops. Accounting for them in mptcp_rcvbuf_grow() causes the rcvbuf slowly drifting towards tcp_rmem[2]. Remove such accounting. Note that subflows will still account for TCP-level OoO when the MPTCP-level rcvbuf is propagated. This also closes a subtle and very unlikely race condition with rcvspace init; active sockets with user-space holding the msk-level socket lock, could complete such initialization in the receive callback, after that the first OoO data reaches the rcvbuf and potentially triggering a divide by zero Oops.
Quoted source text, attributed separately from HOL analysis.