How severe is CVE-2023-3866?

CVE-2023-3866 has a CVSS 3.x base score of 5.5, rated medium severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2023-3866 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 14% (96th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2023-3866?

CVE-2023-3866 primarily affects Linux Linux Kernel. In total, 8 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2023-3866?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2023-3866 have an EU (EUVD) identifier?

Yes. CVE-2023-3866 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2023-44494.

When was CVE-2023-3866 published?

CVE-2023-3866 was published on 2025-08-16 and last updated on 2026-06-17.

CVE-2023-3866

CVE-2023-3866 is a medium-severity vulnerability in Linux Linux Kernel with a CVSS 3.x base score of 5.5. Its EPSS exploit-prediction score of 14% places it in the 96th percentile, indicating an elevated likelihood of exploitation. The underlying weakness is classified as CWE-476.

Key facts

Severity: Medium (CVSS 3.x base score 5.5)
EPSS exploit prediction: 14% (96th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2023-44494
Weakness: CWE-476
Affected product: Linux Linux Kernel
Published: 2025-08-16
Last modified: 2026-06-17

Description

In the Linux kernel, the following vulnerability has been resolved: ksmbd: validate session id and tree id in the compound request This patch validate session id and tree id in compound request. If first operation in the compound is SMB2 ECHO request, ksmbd bypass session and tree validation. So work->sess and work->tcon could be NULL. If secound request in the compound access work->sess or tcon, It cause NULL pointer dereferecing error.

Frequently asked questions

What is CVE-2023-3866?: In the Linux kernel, the following vulnerability has been resolved: ksmbd: validate session id and tree id in the compound request This patch validate session id and tree id in compound request. If first operation in the compound is SMB2 ECHO request, ksmbd bypass session and tree validation. So work->sess and work->tcon could be NULL. If secound request in the compound access work->sess or tcon, It cause NULL pointer dereferecing error.
How severe is CVE-2023-3866?: CVE-2023-3866 has a CVSS 3.x base score of 5.5, rated medium severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2023-3866 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 14% (96th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2023-3866?: CVE-2023-3866 primarily affects Linux Linux Kernel. In total, 8 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2023-3866?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2023-3866 have an EU (EUVD) identifier?: Yes. CVE-2023-3866 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2023-44494.
When was CVE-2023-3866 published?: CVE-2023-3866 was published on 2025-08-16 and last updated on 2026-06-17.

References

Affected products (8)

cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:6.4:rc1:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:6.4:rc2:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:6.4:rc3:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:6.4:rc4:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:6.4:rc5:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:6.4:rc6:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:6.4:rc7:*:*:*:*:*:*

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