Linux KernelOperating system · Linux
CVE-2026-45972
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 · uneditedIn the Linux kernel, the following vulnerability has been resolved: smb: client: fix potential UAF and double free in smb2_open_file() Zero out @err_iov and @err_buftype before retrying SMB2_open() to prevent an UAF bug if @data != NULL, otherwise a double free.
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 confidenceIn the Linux kernel SMB client, the smb2_open_file() function has a memory management bug. When retrying a failed SMB2_open() call, the @err_iov and @err_buftype variables are not zeroed out. If @data is not NULL, this causes a use-after-free (UAF) where previously freed memory is accessed, or a double-free where the same memory is freed twice, leading to potential code execution. The fix requires zeroing these variables before the retry loop.
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
>= 6.1.163, < 6.1.165>= 6.6.124, < 6.6.128>= 6.12.70, < 6.12.75>= 6.18.10, < 6.18.14>= 6.19.1, < 6.19.4= 6.19CVSS 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
- High
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
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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Check installed kernel versionRun `uname -r` or `cat /proc/version` to get the running kernel versionAffected if The kernel version falls within any of these ranges: >= 6.1.163 and < 6.1.165; >= 6.6.124 and < 6.6.128; >= 6.12.70 and < 6.12.75; >= 6.18.10 and < 6.18.14; >= 6.19.1 and < 6.19.4; or exactly 6.19
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Verify SMB client module is loadedRun `lsmod | grep -E 'cifs|smb3|smb2'` to check if the CIFS/SMB kernel modules are loadedAffected if Any SMB client kernel module (cifs, smb3, smb2) is loaded in memory
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Check for active SMB/CIFS mountsRun `mount -t cifs` or `cat /proc/mounts | grep -E 'cifs|smb'` to list any mounted SMB sharesAffected if There are active CIFS or SMB mounts using the kernel SMB client
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Identify potential retry scenariosMonitor for SMB connection errors or disconnections that would trigger retry logic in the kernel log (dmesg or journalctl -k)Affected if The system has SMB mounts that experience connection failures requiring retries, which exercises the vulnerable smb2_open_file retry code path
You are affected if your running kernel version is within the affected ranges AND the SMB client module is loaded AND you have active SMB mounts that could trigger retry operations.
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.
dbcve · scoped6.1.1656.6.1286.12.75
Apply the upstream kernel patch to zero out @err_iov and @err_buftype before retrying, or update to a kernel version containing this fix. Given the critical CVSS 9.8 rating and kernel-level impact, prioritize rapid deployment.
Linux Kernel 6.1.165, 6.6.128, 6.12.75, or 6.18.14 (depending on your active branch)
- Identify the currently running kernel version using 'uname -r'
- Download and install the appropriate fixed kernel version for your distribution: upgrade to kernel 6.1.165 or later for 6.1.x series, 6.6.128 or later for 6.6.x series, 6.12.75 or later for 6.12.x series, or 6.18.14 or later for 6.18.x series
- Reboot the system to load the patched kernel
- Verify the kernel version after reboot with 'uname -r' to confirm the fix is applied
Generated from the published advisory — verify against the referenced sources before acting.
Fix this in Linux Kernel
Scoped from the published advisory
- Consultation2.0 h
- Implementation1.0 h
- Testing8.0 h
- Review / QA3.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,712.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-45972 — 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-2026-45972 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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- Version or environment caveats, and links to real fixes
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