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CVE-2025-39943

Linux Kernel out-of-bounds read

9.4 CRITICALEPSS 0.26%
  1. Published4 Oct 2025

Description

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.

CVSS 3.1 breakdown

Attack vectorNetwork
Attack complexityLow
Privileges requiredNone
User interactionNone
ScopeUnchanged
ConfidentialityHigh
IntegrityLow
AvailabilityHigh
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:H

Affected products

Linux Kernel≥ 5.15.1 < 5.15.194 · ≥ 5.16 < 6.1.154 · ≥ 6.13 < 6.16.9 · ≥ 6.2 < 6.6.108

Frequently asked

Is CVE-2025-39943 being actively exploited?

CVE-2025-39943 is not in the CISA KEV catalog. Its EPSS exploit probability is 0.26%.

How severe is CVE-2025-39943?

CVE-2025-39943 has a CVSS 3.1 base score of 9.4, rated critical. EPSS estimates a 0.26% probability of exploitation.

Which products are affected by CVE-2025-39943?

Affected products include Linux Kernel.

How do I fix CVE-2025-39943?

Upgrade affected software to a fixed version, for example Linux Kernel 5.15.194 or later, then confirm no affected versions remain in your inventory.

How Secuno handles this

Secuno correlates vulnerabilities like CVE-2025-39943 against the real software inventory on every managed device, every day. Rather than a static severity, each match is scored in context: exploit availability, EPSS, the asset's exposure, and business criticality decide where it lands in the queue. If an affected version is present anywhere across your portfolio, it surfaces automatically with a prioritised remediation path.

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Data from the NVD, CISA KEV catalog and FIRST EPSS. CVSS 3.1 base score shown where available.