Traffic ServerApplication · Apache
CVE-2021-32567
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 · uneditedImproper Input Validation vulnerability in HTTP/2 of Apache Traffic Server allows an attacker to DOS the server. This issue affects Apache Traffic Server 7.0.0 to 7.1.12, 8.0.0 to 8.1.1, 9.0.0 to 9.0.1.
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 confidenceImproper input validation in Apache Traffic Server's HTTP/2 implementation allows remote attackers to cause a Denial of Service by sending specially crafted HTTP/2 requests that trigger the validation failure, crashing the server.
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
Traffic ServerApplication
>= 7.0.0, <= 7.1.12>= 8.0.0, <= 8.1.1>= 9.0.0, <= 9.0.1
Debian LinuxOperating system
= 10.0CVSS 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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Verify Apache Traffic Server is installed and runningRun 'traffic_server -V' to get the version, or 'ps aux | grep traffic_server' to check if the process is runningAffected if The command returns a version number that falls within 7.0.0-7.1.12, 8.0.0-8.1.1, or 9.0.0-9.0.1
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Confirm HTTP/2 protocol support is enabledCheck the proxy.config.http2.enabled setting in records.config (typically in /etc/trafficserver/) using 'traffic_ctl config get proxy.config.http2.enabled'Affected if The returned value is 1 (enabled), meaning HTTP/2 connections are accepted
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Check HTTP/2 configuration in remap rulesInspect remap.config or the active plugin configuration for any http2-to-http/2 mapping rules using 'traffic_ctl config get' or by examining the config files in the configuration directoryAffected if HTTP/2 is configured as an upstream protocol or enabled in any traffic handling rules
The environment is affected if Apache Traffic Server is running a version between 7.0.0-7.1.12, 8.0.0-8.1.1, or 9.0.0-9.0.1 AND HTTP/2 protocol support is enabled in the configuration.
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 Apache Traffic Server to version 9.0.2 or later (or the latest stable release). If immediate patching is not possible, consider disabling HTTP/2 and using HTTP/1.1 as a temporary workaround.
Fix this in Traffic Server
Scoped from the published advisory
- Consultation2.0 h
- Implementation2.0 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 $1,984.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-32567 — 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-2021-32567 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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