CVE-2022-22040
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 · uneditedInternet Information Services Dynamic Compression Module 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 confidenceThis is a denial of service vulnerability in Microsoft Internet Information Services (IIS) Dynamic Compression Module. The flaw allows remote attackers to send specially crafted requests that cause the IIS worker process to become unresponsive or crash, disrupting service availability.
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= 21h1= 21h2= 1607= 1809all versionsall versionsall versionsall versionsall versions= r2all versions= r2all versions= 20h2CVSS 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
- Low
- Integrity
- Low
- Availability
- Low
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L
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 IIS is installedRun 'Get-WindowsFeature Web-Server' in PowerShell (Windows Server) or check for IIS in Windows Features (Windows 10/11). Alternatively, look for the w3wp.exe process or check that the IIS W3SVC service exists.Affected if IIS is not installed on the system, the vulnerability does not apply.
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Verify dynamic compression is enabledOpen IIS Manager, select the server node, and check 'Compression' under 'IIS'. Alternatively, run 'appcmd list config /section:urlCompression' or inspect the applicationHost.config file (located in %windir%\System32\inetsrv\config) for 'doStaticCompression' and 'doDynamicCompression' set to 'true'.Affected if Dynamic compression (doDynamicCompression) is not enabled, the vulnerability cannot be exploited.
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Identify the Windows versionRun 'winver' or 'systeminfo | findstr /B /C:"OS Name" /C:"OS Version"' to determine the exact Windows version and build number.Affected if The installed Windows version falls within the affected ranges listed for this CVE.
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Check for installed IIS versionRun 'appcmd list config -section:system.webServer/serverRuntime' or inspect the IIS metabase via PowerShell: 'Get-ItemProperty IIS:\Sites\Default Web Site -Name enabledProtocols'. The IIS version is typically the same as the Windows version (IIS 10.0 on Windows 10/11/Server 2016+).Affected if IIS 10.0 on affected Windows versions is likely vulnerable if dynamic compression is on.
A system is affected if it runs a Windows version listed in the affected products, has IIS installed with the Dynamic Compression Module enabled, and has not applied the CVE-2022-22040 security update.
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 for CVE-2022-22040 to affected IIS installations. If dynamic compression is not required for the environment, it can be disabled in IIS Manager as a temporary mitigation.
- Consultation2.0 h
- Implementation3.0 h
- Testing2.0 h
- Review / QA1.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2022-22040 — 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-2022-22040 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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- 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