CVE-2020-6937
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 Denial of Service vulnerability in MuleSoft Mule CE/EE 3.8.x, 3.9.x, and 4.x released before April 7, 2020, could allow remote attackers to submit data which can lead to resource exhaustion.
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 · moderate confidenceA Denial of Service vulnerability in MuleSoft Mule ESB versions 3.8.x, 3.9.x, and 4.x prior to April 7, 2020 allows remote attackers to submit specially crafted data that leads to resource exhaustion, potentially rendering the service unavailable.
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>= 3.8.0, <= 3.8.7>= 3.9.0, <= 3.9.4>= 4.0.0, <= 4.3.0CVSS 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.
-
Locate the Mule Runtime installationIdentify the MuleSoft Mule ESB installation directory, typically found under /opt/mule, /usr/local/mule, or C:\Program Files\Mule on Windows servers. Check the $MULE_HOME directory structure.Affected if The installation directory exists and contains Mule runtime components.
-
Determine the installed Mule Runtime versionOpen the wrapper.conf file located in the $MULE_HOME/conf directory and locate the wrapper.java.classpath or check the manifest file in $MULE_HOME/lib for mule-core-*.jar. The version number appears in the filename (e.g., mule-core-3.8.7.jar) or as a product.version property in wrapper.conf.Affected if The version cannot be determined or the Mule installation is not found.
-
Compare installed version against affected rangesIf the version is found, verify it falls within any of these ranges: 3.8.0 through 3.8.7, 3.9.0 through 3.9.4, or 4.0.0 through 4.3.0. Note that versions prior to April 7, 2020 in these ranges are vulnerable.Affected if The installed version is 3.8.0-3.8.7, 3.9.0-3.9.4, or 4.0.0-4.3.0 and was not patched after April 7, 2020.
-
Assess network exposure of the Mule serviceDetermine if the Mule ESB HTTP/HTTPS endpoints are accessible from untrusted networks. Check firewall rules, load balancer configurations, and the Mule deployment network topology to see if the service listens on public or DMZ network interfaces.Affected if The Mule service HTTP/HTTPS ports are exposed to the internet or untrusted external networks.
-
Review recent security patchesCheck the $MULE_HOME directory and any patch management records for security updates applied on or after April 7, 2020. Look for patch files or check with the Anypoint Runtime Manager for installed hotfixes.Affected if No security patches from April 7, 2020 or later have been applied to the installation.
You are affected if your Mule Runtime version falls within 3.8.0-3.8.7, 3.9.0-3.9.4, or 4.0.0-4.3.0 and the service is network-accessible to remote attackers without having received post-April-7-2020 security patches.
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 MuleSoft Mule to version 4.1.0 or later (for 4.x) or apply vendor patches for 3.8.x and 3.9.x released on or after April 7, 2020. Implement rate limiting and input validation as compensating controls.
- Consultation4.0 h
- Implementation8.0 h
- Testing8.0 h
- Review / QA4.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $6,656.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2020-6937 — 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-2020-6937 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
Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.
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.
- 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