CVE-2020-6937: A Denial of Service vulnerability in MuleSoft Mule CE/EE 3.8.x, 3.9.x, and 4.x released before April 7, 2020,

This month

HIGH 7.5REMOTEUPGRADE

CVE-2020-6937 is a high-severity flaw (CVSS 7.5) affecting mule runtime. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

A 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.

Why this priority

High severity
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	7.5 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	1.2% (top 31%)
CISA exploited list	No
Published	2020-05-29
Last modified	2026-06-17

Publisher (CNA): Salesforce, Inc. · Vendor: mulesoft

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2020-05-29 22:15 UTCPublished CVE record published
2026-06-17 03:23 UTCUpdated Record last modified

mulesoft mule runtime UPGRADE

Affected: >= 3.8.0 and <= 3.8.7 · >= 3.9.0 and <= 3.9.4 · >= 4.0.0 and <= 4.3.0

Fixed in: newer than 4.3.0

Safe to downgrade to: a release before 3.8.0

1. Check installed version

apt-cache policy mule-runtime || rpm -q mule-runtime || mule-runtime --version

2. UPGRADE to newer than 4.3.0 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade mule-runtime

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade mule-runtime

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

3. If no update is available yet, DOWNGRADE to a release before 3.8.0 (Debian / Ubuntu)

apt-cache madison mule-runtime sudo apt install mule-runtime=<VERSION_BEFORE_3.8.0> sudo apt-mark hold mule-runtime

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list mule-runtime sudo dnf downgrade mule-runtime-<VERSION_BEFORE_3.8.0> sudo dnf versionlock add mule-runtime

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2020-6937?

mule runtime: upgrade to newer than 4.3.0. Exact commands for each OS are on this page.

Is CVE-2020-6937 being exploited?

CVE-2020-6937 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2020-6937 affect?

CVE-2020-6937 affects mule runtime. Severity is high (CVSS 7.5). A 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.

How urgent is CVE-2020-6937?

Priority 49/100. High severity; Remotely exploitable, no login, no user action

Related CVEs

CVE-2019-15631 CRITICAL 9.8 UPGRADE UPGRADE Remote Code Execution vulnerability in MuleSoft Mule CE/EE 3.x and API Gateway 2.x released before October 31,
CVE-2019-15630 HIGH 7.5 MITIGATE UPGRADE Directory Traversal in APIkit, HTTP connector, and OAuth2 Provider components in MuleSoft Mule Runtime 3.2.0 a
CVE-2019-13116 CRITICAL 9.8 UPGRADE The MuleSoft Mule Community Edition runtime engine before 3.8 allows remote attackers to execute arbitrary cod

References

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