Traffic ServerApplication · Apache
CVE-2020-9494
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 · uneditedApache Traffic Server 6.0.0 to 6.2.3, 7.0.0 to 7.1.10, and 8.0.0 to 8.0.7 is vulnerable to certain types of HTTP/2 HEADERS frames that can cause the server to allocate a large amount of memory and spin the thread.
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 confidenceApache Traffic Server versions 6.0.0 to 6.2.3, 7.0.0 to 7.1.10, and 8.0.0 to 8.0.7 is vulnerable to denial-of-service attacks via specially crafted HTTP/2 HEADERS frames that trigger excessive memory allocation and thread spinning.
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
>= 6.0.0, <= 6.2.3>= 7.0.0, <= 7.1.10>= 8.0.0, <= 8.0.7
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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Determine installed Apache Traffic Server versionRun 'traffic_server -v' or 'traffic_ctl server version' to get the exact version number. On Debian systems, also check via 'dpkg -l | grep trafficserver'Affected if The installed version falls within 6.0.0 to 6.2.3, 7.0.0 to 7.1.10, or 8.0.0 to 8.0.7
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Locate the Traffic Server configuration directoryCommon locations include /etc/trafficserver/ (Debian) or /usr/local/etc/trafficserver/ (source install). Look for records.configAffected if Configuration file exists and contains HTTP/2 settings (needed for next check)
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Check if HTTP/2 protocol is enabledInspect records.config for the setting 'proxy.config.http2.enabled' or similar HTTP/2 configuration options. Run 'traffic_ctl config get proxy.config.http2.enabled' if availableAffected if HTTP/2 is explicitly enabled (value set to 1 or on)
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Verify HTTP/2 is actively listeningCheck for HTTP/2 port definitions in records.config under 'CONFIG proxy.config.http2.server_max_streams' or similar HTTP/2 listener settings. Also check ssl.multicert.config if TLS/H2 is usedAffected if HTTP/2 ports or streams are configured and active
You are affected if your Apache Traffic Server version is between 6.0.0-6.2.3, 7.0.0-7.1.10, or 8.0.0-8.0.7 AND HTTP/2 protocol is enabled in your 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 6.2.4, 7.1.11, 8.0.8, or later. If HTTP/2 is not required, it can be disabled 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-2020-9494 — 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-2020-9494 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
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