Linux KernelOperating system · Linux
CVE-2023-39176
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedA flaw was found within the parsing of SMB2 requests that have a transform header in the kernel ksmbd module. The issue results from the lack of proper validation of user-supplied data, which can result in a read past the end of an allocated buffer. An attacker can leverage this to disclose sensitive information on affected installations of Linux. Only systems with ksmbd enabled are vulnerable to this CVE.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · high confidenceAn out-of-bounds read vulnerability exists in the Linux kernel's ksmbd SMB server module when parsing SMB2 requests containing transform headers. The flaw stems from insufficient validation of user-supplied data during parsing, allowing an attacker to read past the end of an allocated buffer and disclose sensitive information. Only systems with ksmbd enabled are affected.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data
Linux KernelOperating system
all versionsCVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- None
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Verify if ksmbd kernel module is loadedRun `lsmod | grep ksmbd` to check if the ksmbd module is currently loaded in the kernelAffected if The ksmbd module appears in the output and is actively loaded
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Check if ksmbd is built into the kernelRun `cat /proc/config.gz 2>/dev/null | gunzip | grep KSMBD` or check the kernel config file in /boot/ or /lib/modules/ to see if CONFIG_KSMBD is set to yAffected if CONFIG_KSMBD is set to y (built-in) rather than m (module) or n (disabled)
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Confirm ksmbd service or daemon statusRun `systemctl status ksmbd` (if using the userspace daemon) or check for ksmbd-related processes with `ps aux | grep -i ksmbd`Affected if The ksmbd service daemon is running or ksmbd-related processes are active
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Identify kernel versionRun `uname -r` to obtain the exact kernel version running on the systemAffected if The kernel version matches the vulnerable version range for this CVE (compare against vendor advisory for specific version details)
A system is affected if ksmbd is enabled (either as a loaded module, built-in to the kernel, or actively running as a service) and the kernel version falls within the vulnerable range for this CVE.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
From vendor dataIf ksmbd is not required, disable or unload the ksmbd kernel module. Otherwise, apply available kernel security patches that address this vulnerability. Monitor for vendor patch releases and implement them according to your patch management policy.
Fix this in Linux Kernel
Scoped from the published advisory
- Consultation3.0 h
- Implementation2.0 h
- Testing4.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,072.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2023-39176 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2023-39176 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.
- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
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