dbcve.org
TomcatWeb server / proxy · Apache

CVE-2017-5647

HIGH · 7.5 CVSS v3.0 Published 2017-04-17
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
84/100
Remediation priority · High
Remotely reachable No privileges Zero-click

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 · unedited
A bug in the handling of the pipelined requests in Apache Tomcat 9.0.0.M1 to 9.0.0.M18, 8.5.0 to 8.5.12, 8.0.0.RC1 to 8.0.42, 7.0.0 to 7.0.76, and 6.0.0 to 6.0.52, when send file was used, results in the pipelined request being lost when send file processing of the previous request completed. This could result in responses appearing to be sent for the wrong request. For example, a user agent that sent requests A, B and C could see the correct response for request A, the response for request C for request B and no response for request C.

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 confidence

A bug in Apache Tomcat's handling of pipelined HTTP requests when send file processing is used causes pipelined requests to be lost after the previous request's send file completes. This results in responses being sent for the wrong request, causing request/response mismatch (e.g., request A gets response A, request B gets response C, request C gets no response).

MitigationUpgrade Apache Tomcat to version 9.0.0.M19 or later, 8.5.13 or later, 8.0.43 or later, 7.0.77 or later, or 6.0.53 or later to obtain the patched connector handling.

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
TomcatWeb server / proxy
Affected:= 6.0.0= 6.0.1= 6.0.2= 6.0.3= 6.0.4= 6.0.5= 6.0.6= 6.0.7= 6.0.8= 6.0.9= 6.0.10= 6.0.11

CVSS 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
High
Integrity
None
Availability
None

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

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 checks

Work through these to decide whether this CVE applies to you.

  1. Identify Apache Tomcat installation location and version
    Locate the Tomcat installation directory. Check the version by examining the RELEASE-NOTE file in the Tomcat home directory, or run: java -cp catalina.jar org.apache.catalina.util.ServerInfo
    Affected if The installed version is 6.0.0 through 6.0.11 inclusive (any 6.0.x version up to and including 6.0.11)
  2. Confirm the connector type in use
    Examine the server.xml configuration file in the Tomcat conf directory. Look for the <Connector> element definitions. Identify if NIO or NIO2 connector is configured (e.g., protocol="org.apache.coyote.http11.NioProtocol" or protocol="org.apache.coyote.http11.Nio2Protocol")
    Affected if NIO or NIO2 connector is in use (the vulnerability exists in the NIO implementation)
  3. Verify HTTP pipelining support is enabled
    Check the server.xml Connector element for the attribute pipeline.enable="true" (or if absent, pipelining is enabled by default in Tomcat). Ensure the connector has not explicitly set pipeline.enable="false"
    Affected if HTTP pipelining is enabled (this is the default and required for the vulnerability to trigger)
  4. Confirm send file processing is in use
    Check the Connector configuration in server.xml. Look for the sendfile attribute (e.g., sendfile="true") or examine if the default sendfile configuration applies. This feature is typically enabled for serving static files efficiently
    Affected if Send file processing is enabled or in use (this is typically enabled by default for static file serving and is required for the flaw to manifest)

A user is affected if they run Apache Tomcat 6.0.x (versions 6.0.0 through 6.0.11) with NIO/NIO2 connectors, HTTP pipelining enabled, and send file processing active - all three conditions must be present for the request/response mismatch to occur.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

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 data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Upgrade Apache Tomcat to version 9.0.0.M19 or later, 8.5.13 or later, 8.0.43 or later, 7.0.77 or later, or 6.0.53 or later to obtain the patched connector handling.

Fix this in Tomcat Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing4.0 h
  • Review / QA2.0 h
12.0 hours of engineering $2,080
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2017-5647 in production — separate from our analysis above.

No notes yet

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What this is

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.

What belongs here
  • 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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