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VarnishApplication · Varnish.projects.linpro

CVE-2009-2936

HIGH · 7.5 CVSS v2.0 Published 2010-04-05
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
High EPSS 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
The Command Line Interface (aka Server CLI or administration interface) in the master process in the reverse proxy server in Varnish before 2.1.0 does not require authentication for commands received through a TCP port, which allows remote attackers to (1) execute arbitrary code via a vcl.inline directive that provides a VCL configuration file containing inline C code; (2) change the ownership of the master process via param.set, stop, and start directives; (3) read the initial line of an arbitrary file via a vcl.load directive; or (4) conduct cross-site request forgery (CSRF) attacks that leverage a victim's location on a trusted network and improper input validation of directives. NOTE: the vendor disputes this report, saying that it is "fundamentally misguided and pointless.

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

The Varnish reverse proxy server's Command Line Interface (CLI) in versions before 2.1.0 lacks authentication on its management TCP port, allowing unauthenticated remote attackers to execute arbitrary code through vcl.inline directives containing inline C code, manipulate master process ownership via param.set/start/stop directives, read arbitrary file contents via vcl.load, and conduct CSRF attacks.

MitigationUpgrade to Varnish 2.1.0 or later to patch the vulnerability; alternatively, ensure the management CLI port is not exposed to untrusted networks by using firewall rules or binding to localhost only.

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
VarnishApplication
Affected:= 0.9= 0.9.1= 1.0= 1.0.1= 1.0.2= 1.0.3= 1.0.4= 1.1= 1.1.1= 1.1.2= 2.0= 2.0.1

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
Authentication
None
Confidentiality
Partial
Integrity
Partial
Availability
Partial

AV:N/AC:L/Au:N/C:P/I:P/A:P

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 Varnish version
    Run command: varnishd -V or rpm -q varnish or dpkg -l varnish depending on your system
    Affected if Version is 0.9, 0.9.1, 1.0, 1.0.1, 1.0.2, 1.0.3, 1.0.4, 1.1, 1.1.1, 1.1.2, 2.0, or 2.0.1 (any version before 2.1.0)
  2. Locate Varnish configuration file
    Common paths: /etc/varnish/default.vcl or check VARNISH_CONFIG in environment or init script
    Affected if Configuration file exists and Varnish is configured to run
  3. Check management CLI port binding
    Inspect Varnish startup parameters for -s or -f arguments; look for 'listen' or 'management' directives in configuration; run: ps aux | grep varnishd to see startup flags
    Affected if Management port (default 6082) is bound to 0.0.0.0 or a publicly reachable interface rather than 127.0.0.1 only
  4. Verify firewall exposure of management port
    Check iptables rules or host firewall configuration for rules allowing external access to port 6082 (or custom CLI port)
    Affected if Port 6082 or the configured management port is accessible from untrusted networks or non-localhost addresses
  5. Confirm CLI authentication status
    Attempt a local connection to management port: telnet localhost 6082 or nc localhost 6082, then issue a simple command like 'ping' without providing credentials
    Affected if CLI accepts commands without requiring authentication

You are affected if running any Varnish version before 2.1.0 AND the management CLI port is accessible from untrusted network segments without authentication.

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 to Varnish 2.1.0 or later to patch the vulnerability; alternatively, ensure the management CLI port is not exposed to untrusted networks by using firewall rules or binding to localhost only.

Fix this in Varnish Scoped from the published advisory
  • Consultation3.0 h
  • Implementation4.0 h
  • Testing2.0 h
  • Review / QA1.0 h
10.0 hours of engineering $1,800
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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-2009-2936 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
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