NULL pointer dereference in Linux

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.

Published · last modified .

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

EPSS exploit prediction

EPSS: 0.111 (95.8th percentile), scored .

Moderate probability of exploitation in the next 30 days — watch for active exploitation reports. 96th percentile — 95.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2023-3866: rose from 0.096 to 0.111.

EPSS over last 30 days · oldest: 0.096 · newest: 0.111 · change: +0.014

Affected products

  • Linux — versions 0626e6641f6b467447c81dd7678a69c66f7746cf, 5.15, 0
  • Linux Kernel — versions 6.4

Weakness classification (CWE)

Public proof-of-concept exploits

References

Frequently asked questions

What is CVE-2023-3866?
CVE-2023-3866 is a high-severity vulnerability in Linux, classified under NULL Pointer Dereference. CVSS score: 7.5/10. Published 2025-08-16.
How severe is CVE-2023-3866?
High severity. CVSS v3 base score is 7.5 out of 10.
Is CVE-2023-3866 known to be exploited?
3 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.