CVE-2018-6332
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 potential denial-of-service issue in the Proxygen handling of invalid HTTP2 settings which can cause the server to spend disproportionate resources. This affects all supported versions of HHVM (3.24.3 and 3.21.7 and below) when using the proxygen server to handle HTTP2 requests.
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 confidenceA denial-of-service vulnerability exists in the Proxygen HTTP server library used by HHVM where processing invalid HTTP2 settings frames causes disproportionate resource consumption, potentially rendering the server unresponsive.
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<= 3.21.7= 3.24.3CVSS 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
- High
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- None
- Availability
- High
CVSS:3.1/AV:N/AC:H/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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Identify HHVM installation and versionRun 'hhvm --version' or check the installed package version via your package manager (e.g., dpkg -l hhvm, rpm -qi hhvm)Affected if The installed version is 3.21.7 or lower, or exactly 3.24.3
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Verify Proxygen server is in useCheck the HHVM configuration file (typically /etc/hhvm/server.ini or similar) for 'server.type = proxygen' or examine how HHVM was started for the Proxygen server flagAffected if HHVM is configured to use the Proxygen server type
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Confirm HTTP/2 support is enabledInspect the HHVM configuration for 'hhvm.server.http2 = true' or check if the server is listening with HTTP/2 protocol support (e.g., via netstat/ss or configuration review)Affected if HTTP/2 protocol handling is enabled in the HHVM Proxygen configuration
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Check for exposed HTTP endpointsReview the server configuration to identify if the Proxygen server is directly exposed to network requests rather than behind a reverse proxyAffected if The Proxygen server handles external or untrusted HTTP/2 connections directly
You are affected if HHVM with Proxygen is running an affected version (3.21.7 or lower, or exactly 3.24.3) with HTTP/2 enabled and handling requests directly.
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 dataUpgrade HHVM to version 3.24.4 or 3.21.8 or higher when using the Proxygen server to handle HTTP2 requests, as these versions contain the fix for the malformed settings handling.
- Consultation2.0 h
- Implementation2.0 h
- Testing2.0 h
- Review / QA1.0 h
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Free · runs locallyCheck whether your project pulls in CVE-2018-6332 — 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-2018-6332 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
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