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Debian LinuxOperating system · Debian

CVE-2018-7556

CRITICAL · 9.1 CVSS v3.0 Published 2018-02-28
Fix available
A fix is available. Upgrade to 2.6.7 / 2.73.1 or later.
See remediation →
100/100
Remediation priority · Urgent
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
LimeSurvey 2.6.x before 2.6.7, 2.7x.x before 2.73.1, and 3.x before 3.4.2 mishandles application/controller/InstallerController.php after installation, which allows remote attackers to access the configuration file.

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

LimeSurvey fails to properly secure or remove the installer after installation completes, leaving InstallerController.php accessible. This allows unauthenticated remote attackers to access the configuration file, which typically contains database credentials, encryption keys, and other sensitive system details, leading to complete application compromise.

MitigationImmediately either update LimeSurvey to version 2.6.7+, 2.73.1+, or 3.4.2+ OR remove the entire /application/controllers/ and/or /installer/ directory from production deployments. Rotate all credentials that may have been exposed.

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
Debian LinuxOperating system
Affected:= 7.0
LimesurveyApplication
Affected:>= 2.6.0, < 2.6.7>= 2.7.0, < 2.73.1>= 3.0.0, < 3.4.2

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

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

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 LimeSurvey version
    Locate and read the version file - typically found at application/config/version.php or look for a version constant in the application. Compare the version number against the affected ranges: 2.6.0-2.6.6, 2.7.0-2.73.0, 3.0.0-3.4.1
    Affected if Installed version falls within any of the affected ranges (2.6.0-2.6.6, 2.7.0-2.73.0, 3.0.0-3.4.1)
  2. Verify installer directory removal
    Check if the /installer directory exists in the web root. On Linux, run: ls -la /path/to/webroot/installer/ or check via file manager
    Affected if The /installer directory exists in the web root and has not been removed post-installation
  3. Confirm InstallerController.php presence
    Check if InstallerController.php exists in application/controllers/ directory. Run: ls -la application/controllers/InstallerController.php
    Affected if InstallerController.php file exists in the controllers directory and is accessible
  4. Test installer endpoint accessibility
    Attempt to access the installer via HTTP: curl http://your-site/index.php?r=installer or http://your-site/installer/ (depending on version). A successful response (not 404 or redirect) indicates the installer is exposed
    Affected if The installer endpoint returns a valid response and is accessible without authentication

You are affected if LimeSurvey version is 2.6.0-2.6.6, 2.7.0-2.73.0, or 3.0.0-3.4.1 AND the installer directory or InstallerController.php remains accessible on the web server.

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 2.6.7 / 2.73.1 / 3.4.2 or later
Fixed in 2.6.72.73.13.4.2
Interim mitigation

Immediately either update LimeSurvey to version 2.6.7+, 2.73.1+, or 3.4.2+ OR remove the entire /application/controllers/ and/or /installer/ directory from production deployments. Rotate all credentials that may have been exposed.

Recommended fix High confidence

LimeSurvey 2.6.7+ / 2.73.1+ / 3.4.2+ (depending on your branch)

  1. Backup the current LimeSurvey installation and database before proceeding
  2. Identify the current LimeSurvey version in use (2.6.x, 2.7.x, or 3.x)
  3. For LimeSurvey 2.6.x: Upgrade to version 2.6.7 or later
  4. For LimeSurvey 2.7.x: Upgrade to version 2.73.1 or later
  5. For LimeSurvey 3.x: Upgrade to version 3.4.2 or later
  6. After upgrade, verify that application/controller/InstallerController.php is no longer accessible or has been removed
  7. Confirm the configuration file (config.php) is no longer exposed via the installer path
  8. Test that the LimeSurvey application functions normally after upgrade
Caveat Review LimeSurvey release notes for your specific version branch for any breaking changes between your current version and the target upgrade version

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

Fix this in Debian Linux Scoped from the published advisory
  • Consultation3.0 h
  • Implementation2.0 h
  • Testing2.0 h
7.0 hours of engineering $1,260
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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-2018-7556 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