CVE-2023-21758
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 · uneditedWindows Internet Key Exchange (IKE) Extension Denial of Service Vulnerability
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 · moderate confidenceA denial-of-service vulnerability exists in the Windows Internet Key Exchange (IKE) extension. An unauthenticated remote attacker can send specially crafted network packets to cause the affected system to stop responding, resulting in a denial of service condition.
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 dataall versions= 20h2= 21h2= 22h2= 1607= 1809all versions= 21h2= 22h2all versionsall versionsall 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
- None
- Integrity
- None
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/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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Confirm Windows version matches affected rangeRun 'winver' or 'systeminfo | findstr /B /C:"OS Name" /C:"OS Version"' to identify the installed Windows version and build numberAffected if The system runs Windows 10 (any build), Windows 11 (21h2, 22h2), Windows Server 2016, 2019, or 2022 - compare your version to the listed affected versions
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Verify IKEEXT service statusOpen Services (services.msc) or run 'Get-Service IKEEXT' in PowerShell to check if the IKE and AuthIP IPsec Keying Modules service is present and runningAffected if The IKEEXT service exists on the system (present on all affected Windows versions); if it is running, the IKE extension is active and potentially vulnerable
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Check for IPsec/IKE policy configurationRun 'netsh ipsec dynamic show all' or 'Get-NetIPsecPolicy' in PowerShell to enumerate any IPsec or IKE policies configured on the systemAffected if Any IPsec or IKE policies are configured, indicating the IKE extension is in use and the system may be terminating VPN connections
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Identify internet-facing network exposureReview network adapter configurations and firewall rules to determine if the system has public IP addresses or is directly accessible from the internetAffected if The system has direct internet exposure or terminates IPsec VPN connections, increasing the likelihood of receiving crafted IKE packets
A system is affected if it runs any affected Windows version listed AND has the IKEEXT service present, with risk highest on systems that have IKE/IPsec policies configured and direct network exposure to untrusted sources.
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 dataApply the Microsoft security update addressing CVE-2023-21758 to all affected Windows systems. Prioritize systems with direct internet exposure or those terminating IPsec VPN connections.
- Consultation2.0 h
- Implementation1.0 h
- Testing2.0 h
- Review / QA1.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,696.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2023-21758 — 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-2023-21758 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
- No weaponised exploit code, or anything meant to cause harm
- No spam, self-promotion, credentials, or personal data