CVE-2026-98438mptcp: options: fix uninit-value in mptcp_write_data_fin
Updated under an hour ago ()
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No exploitation reported and no EPSS estimate yet.
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In the Linux kernel, the following vulnerability has been resolved: mptcp: options: fix uninit-value in mptcp_write_data_fin When sending a DATA_FIN without data, and because the DATA_FIN occupies 1 octet of the connection-level sequence space [1], it is then required to add a DSS mapping with specific values. If the checksum has been negotiated, it also needs to be computed, and included in the outgoing packet, and thus the initial csum data needs to be reset to 0 as well. This is no longer the case since commit cfcceb7a39fc ("tcp: shrink per-packet memset in __tcp_transmit_skb()"), because the whole ext_copy structure is no longer zeroed by default. This seems to be the only case where use_map is changed and set afterwards, so initialising the csum field only in this case, along with other fields for this specific case.
- CVSS
- Not yet scored
- Weakness (CWE)
- Not given
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- Linux
- NVD analysis
- Received
- Record last updated
- Oct 18, 2026
- First seen by InfoSec Signals
- Oct 18, 2026
Affected products
Linux Linux linux:linux (from the name) | from cfcceb7a39fc10a6f896af8229bf81d96acb22cc before 9a682067dd7b9dce6b94a0a05661dcc921446402; from cfcceb7a39fc10a6f896af8229bf81d96acb22cc before b110f1dd6cb6a9930503354a01a315e0a821eaa7 | CNA record |
References
- https://git.kernel.org/stable/c/9a682067dd7b9dce6b94a0a05661dcc921446402
- https://git.kernel.org/stable/c/b110f1dd6cb6a9930503354a01a315e0a821eaa7
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.