CVE-2023-3866 | ksmbd: validate session id and tree id in the compound request

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: 2025-08-16 Last update: 2025-11-18 Assigner: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
NVD Status：Analyzed，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2023-3866 is rated Low Risk (24.3/100): CVSS Medium severity, with low exploitation likelihood (EPSS 0.03%). Monitor for updates and reassess as exploit intelligence or EPSS changes.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2023-3866

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2025-08-17 — 0.03% —

Full EPSS history (1 record total)

Common vulnerability scoring system (CVSS) metrics for CVE-2023-3866

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
5.5 3.1 MEDIUM
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:L)
They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 1.8 3.6 [email protected]

Weakness enumeration for CVE-2023-3866

OS Trackers for CVE-2023-3866

vendor priority summary link
debian unimportant CVE-2023-3866 unimportant priority: Debian including 1 source packages (linux), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2023-3866
redhat medium — https://access.redhat.com/security/cve/CVE-2023-3866
ubuntu medium CVE-2023-3866 medium priority: Ubuntu including 167 source packages (linux, linux-allwinner, …), 1873 status rows across 12 suites (bionic, focal, jammy, lunar, mantic, noble, oracular, plucky, questing, trusty, upstream, xenial): DNE 1428, released 165, not-affected 163, ignored 117. https://ubuntu.com/security/CVE-2023-3866

Affected software / configurations for CVE-2023-3866

Vendor Product Version Raw CPE
linux linux_kernel >= 5.15, < 5.15.121 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
linux linux_kernel >= 5.16, < 6.1.36 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
linux linux_kernel >= 6.2, < 6.3.10 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
linux linux_kernel 6.4 cpe:2.3:o:linux:linux_kernel:6.4:rc1:*:*:*:*:*:*
linux linux_kernel 6.4 cpe:2.3:o:linux:linux_kernel:6.4:rc2:*:*:*:*:*:*
linux linux_kernel 6.4 cpe:2.3:o:linux:linux_kernel:6.4:rc3:*:*:*:*:*:*
linux linux_kernel 6.4 cpe:2.3:o:linux:linux_kernel:6.4:rc4:*:*:*:*:*:*
linux linux_kernel 6.4 cpe:2.3:o:linux:linux_kernel:6.4:rc5:*:*:*:*:*:*
linux linux_kernel 6.4 cpe:2.3:o:linux:linux_kernel:6.4:rc6:*:*:*:*:*:*
linux linux_kernel 6.4 cpe:2.3:o:linux:linux_kernel:6.4:rc7:*:*:*:*:*:*

References for CVE-2023-3866

cvelogic Threat Intelligence