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Actively exploited in the wild. This CVE is on the CISA Known Exploited Vulnerabilities list — treat remediation as urgent. Federal remediation due by 15 Apr 2022.
TomcatWeb server / proxy · Apache

CVE-2017-12617

HIGH · 8.1 CVSS v3.1 Published 2017-10-04
Fix available
A fix is available. Upgrade to 7.0.82 / 8.0.47 or later.
See remediation →
100/100
Remediation priority · Urgent
In the wild High EPSS Public exploit Remotely reachable No privileges Zero-click Patch available

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
When running Apache Tomcat versions 9.0.0.M1 to 9.0.0, 8.5.0 to 8.5.22, 8.0.0.RC1 to 8.0.46 and 7.0.0 to 7.0.81 with HTTP PUTs enabled (e.g. via setting the readonly initialisation parameter of the Default servlet to false) it was possible to upload a JSP file to the server via a specially crafted request. This JSP could then be requested and any code it contained would be executed by the server.

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

Apache Tomcat allows remote code execution via JSP file upload when HTTP PUT requests are enabled. Specifically, when the Default servlet's 'readonly' parameter is set to false, an attacker can upload a malicious JSP file through a specially crafted PUT request and then execute it by requesting the uploaded file.

MitigationDisable HTTP PUT functionality by ensuring the Default servlet's 'readonly' parameter remains at its default value of true, or upgrade to patched Tomcat versions (7.0.82+, 8.0.47+, 8.5.23+, 9.0.1+).

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:>= 7.0.0, < 7.0.82>= 8.0, < 8.0.47>= 8.5.0, < 8.5.23>= 9.0.0, < 9.0.1
Ubuntu LinuxOperating system
Affected:= 12.04= 16.04= 17.10= 18.04
Debian LinuxOperating system
Affected:= 7.0
FuseApplication
Affected:= 1.0
Jboss Enterprise Application PlatformApplication
Affected:= 6.0.0= 6.4.0
Jboss Enterprise Web ServerApplication
Affected:= 2.0.0= 3.0.0
Jboss Enterprise Web Server Text Only AdvisoriesApplication
Affected:all versions
Enterprise Linux DesktopOperating system
Affected:= 6.0= 7.0

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
High
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/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 checks

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

  1. Identify installed Apache Tomcat version
    Locate the Tomcat installation directory. Check the RELEASE-NOTES file, or run 'catalina.sh version', or look for a VERSION file in the Tomcat home directory. Alternatively, check the Server header in HTTP responses or the server.info entry in conf/catalina.properties.
    Affected if The version is 7.0.0-7.0.81, 8.0.0-8.0.46, 8.5.0-8.5.22, or 9.0.0-9.0.0 (any version before 7.0.82, 8.0.47, 8.5.23, or 9.0.1).
  2. Locate the Default servlet configuration
    Find the conf/web.xml file in the Tomcat installation. Alternatively, check the application's own web.xml if the Default servlet is overridden. Look for a <servlet> element with <servlet-name>default</servlet-name>.
    Affected if The Default servlet configuration exists in the examined web.xml file.
  3. Check the readonly parameter in the Default servlet
    In the Default servlet configuration, look for an <init-param> with <param-name>readonly</param-name>. If found, check its <param-value>. If the parameter is absent, the default is true (not vulnerable).
    Affected if The readonly parameter is explicitly set to false (case-insensitive), enabling HTTP PUT and DELETE methods.
  4. Verify the JSP servlet is enabled
    In conf/web.xml, locate the JSP servlet configuration (jsp and jsp servlet definitions). Confirm the servlet mappings for *.jsp and *.jspx are active.
    Affected if The JSP servlet is mapped and enabled, allowing uploaded JSP files to be executed.

The environment is affected if Tomcat is a vulnerable version AND the Default servlet has readonly=false, allowing arbitrary JSP file upload and remote code execution.

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.

dbcve · scoped
Upgrade available Upgrade to 7.0.82 / 8.0.47 / 8.5.23 or later
Fixed in 7.0.828.0.478.5.23
Vendor patch www.oracle.com →
Interim mitigation

Disable HTTP PUT functionality by ensuring the Default servlet's 'readonly' parameter remains at its default value of true, or upgrade to patched Tomcat versions (7.0.82+, 8.0.47+, 8.5.23+, 9.0.1+).

Recommended fix High confidence

Tomcat 7.0.82 / 8.0.47 / 8.5.23 / 9.0.1 (or later respective versions)

  1. Identify the currently installed Apache Tomcat version by checking the server logs or tomcat-version.jar
  2. Stop the Tomcat service before making any changes
  3. Download the appropriate fixed Tomcat version: 7.0.82+, 8.0.47+, 8.5.23+, or 9.0.1+ from the official Apache Tomcat site (tomcat.apache.org)
  4. Back up the current Tomcat installation directory (conf, webapps, and any custom deployments)
  5. Extract the new Tomcat version to the target installation directory
  6. Restore the backed-up configuration files (server.xml, context.xml, etc.)
  7. Re-deploy any custom web applications from the backup
  8. Start the Tomcat service and verify it starts without errors
Caveat Minor Tomcat patch upgrades typically have no breaking changes; however, always test in a staging environment before production deployment and ensure custom configurations are compatible

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Tomcat Exploited in the wild — priority engagement
  • Consultation2.0 h
  • Implementation2.0 h
  • Testing4.0 h
  • Review / QA2.0 h
10.0 hours of engineering $1,720
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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-2017-12617 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
  • No spam, self-promotion, credentials, or personal data