CVE-2016-2785: Puppet Server before 2.3.2 and Ruby puppetmaster in Puppet 4.x before 4.4.2 and in Puppet Agent before 1.4.2 m

This week

CRITICAL 9.8REMOTEDOWNGRADEDOWNGRADEDOWNGRADE

CVE-2016-2785 is a critical-severity flaw (CVSS 9.8) affecting puppet, puppet server, puppet agent. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Puppet Server before 2.3.2 and Ruby puppetmaster in Puppet 4.x before 4.4.2 and in Puppet Agent before 1.4.2 might allow remote attackers to bypass intended auth.conf access restrictions by leveraging incorrect URL decoding.

Why this priority

Critical severity
Remotely exploitable, no login, no user action

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	9.8 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	2.9% (top 13%)
CISA exploited list	No
Weakness	CWE-284
Published	2016-06-10
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: puppet

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

Am I affected?

Timeline

2016-06-10 15:59 UTCPublished CVE record published
2026-06-17 00:44 UTCUpdated Record last modified

puppet puppet DOWNGRADE

Affected: 4.0.0 · 4.0.0 rc1 · 4.0.0 rc2 · 4.0.0 rc3 · 4.1.0 · 4.2.0 · 4.2.1 · 4.2.2

Fixed in: no fixed release known

Safe to downgrade to: a release before 4.0.0

1. Check installed version

apt-cache policy puppet || rpm -q puppet || puppet --version

2. No fixed release: DOWNGRADE to a release before 4.0.0 (Debian / Ubuntu)

apt-cache madison puppet sudo apt install puppet=<VERSION_BEFORE_4.0.0> sudo apt-mark hold puppet

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list puppet sudo dnf downgrade puppet-<VERSION_BEFORE_4.0.0> sudo dnf versionlock add puppet

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.

puppet puppet server DOWNGRADE

Affected: 2.0.0 · 2.1.0 · 2.1.1 · 2.1.2 · 2.2.0 · 2.3.0 · 2.3.1

Fixed in: no fixed release known

Safe to downgrade to: a release before 2.0.0

1. Check installed version

apt-cache policy puppet-server || rpm -q puppet-server || puppet-server --version

2. No fixed release: DOWNGRADE to a release before 2.0.0 (Debian / Ubuntu)

apt-cache madison puppet-server sudo apt install puppet-server=<VERSION_BEFORE_2.0.0> sudo apt-mark hold puppet-server

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list puppet-server sudo dnf downgrade puppet-server-<VERSION_BEFORE_2.0.0> sudo dnf versionlock add puppet-server

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.

puppet puppet agent DOWNGRADE

Affected: 1.4.1

Fixed in: no fixed release known

Safe to downgrade to: a release before 1.4.1

1. Check installed version

apt-cache policy puppet-agent || rpm -q puppet-agent || puppet-agent --version

2. No fixed release: DOWNGRADE to a release before 1.4.1 (Debian / Ubuntu)

apt-cache madison puppet-agent sudo apt install puppet-agent=<VERSION_BEFORE_1.4.1> sudo apt-mark hold puppet-agent

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list puppet-agent sudo dnf downgrade puppet-agent-<VERSION_BEFORE_1.4.1> sudo dnf versionlock add puppet-agent

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-2016-2785?

puppet: downgrade or apply the listed mitigation; puppet server: downgrade or apply the listed mitigation; puppet agent: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2016-2785 being exploited?

CVE-2016-2785 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-2016-2785 affect?

CVE-2016-2785 affects puppet, puppet server, puppet agent. Severity is critical (CVSS 9.8). Puppet Server before 2.3.2 and Ruby puppetmaster in Puppet 4.x before 4.4.2 and in Puppet Agent before 1.4.2 might allow remote attackers to bypass intended auth.conf access restrictions by leveraging incorrect URL decoding.

How urgent is CVE-2016-2785?

Priority 61/100. Critical severity; Remotely exploitable, no login, no user action

Software pages

Ruby vulnerabilities

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References

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