CVE-2025-39943

ksmbd: smbdirect: validate data_offset and data_length field of smb_direct_data_transfer

CVE-2025-39943 is fixed in linux on 1 platform, first by DEBIAN-CVE-2025-39943, released October 4, 2025. It is not reported as exploited. Patch Radar priority: Urgent.

Urgent

CVSS

9.8

Critical

Exploitation

None reported

No vendor assessment

CISA KEV

Not listed

Not in the Known Exploited Vulnerabilities catalog

EPSS

0.0026

18th percentile

In the Linux kernel, the following vulnerability has been resolved: ksmbd: smbdirect: validate data_offset and data_length field of smb_direct_data_transfer If data_offset and data_length of smb_direct_data_transfer struct are invalid, out of bounds issue could happen. This patch validate data_offset and data_length field in recv_done.

Where it's fixed

Product	Fixed in	Fix	Released
Linux
linux · Debian 12.15 (bookworm)	6.1.158-1	DEBIAN-CVE-2025-39943	Oct 4, 2025
linux · Debian 13.5 (trixie)	6.12.57-1	DEBIAN-CVE-2025-39943	Oct 4, 2025
linux · Debian 14	6.16.9-1	DEBIAN-CVE-2025-39943	Oct 4, 2025

Details

Published
October 4, 2025
CVSS vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H
Vendor advisory
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-39943

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