Simple Machines ForumApplication · Simple Machines

CVE-2006-7013

HIGH · 7.5 CVSS v2.0 Published 2007-02-15
Fix available
A fix is available. Upgrade to after 1.1_rc2 or later.
See remediation →
84/100
Remediation priority · High
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
QueryString.php in Simple Machines Forum (SMF) 1.0.7 and earlier, and 1.1rc2 and earlier, allows remote attackers to more easily spoof the IP address and evade banning via a modified X-Forwarded-For HTTP header, which is preferred instead of other more reliable sources for the IP address. NOTE: the original researcher claims that the vendor has disputed this issue

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

QueryString.php in Simple Machines Forum (SMF) 1.0.7 and earlier, and 1.1rc2 and earlier, uses the X-Forwarded-For HTTP header as the primary source for determining client IP addresses, rather than using it as a fallback. This allows remote attackers to spoof their IP address by sending a modified X-Forwarded-For header, enabling them to evade IP-based bans and other IP-based security controls.

MitigationModify QueryString.php to prioritize the REMOTE_ADDR server variable for IP detection and treat X-Forwarded-For only as an untrusted fallback with strict validation (e.g., only use the first IP in the chain, reject internal/IPv6 as needed). Implement proper IP ban enforcement using the validated IP.

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
Simple Machines ForumApplication
Affected:<= 1.0.7<= 1.1_rc2

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. Check SMF installation version
    Locate the Settings.php file in your SMF installation root directory. Look for a line defining $db_version or check the version info typically found in the file header or a separate version file. Compare this version number against the affected ranges: 1.0.7 or earlier, or 1.1rc2 or earlier.
    Affected if The installed version is 1.0.7 or lower, or 1.1rc2 or lower.
  2. Locate QueryString.php
    Navigate to your SMF installation directory and find the QueryString.php file, which is typically located in the main forum root directory.
    Affected if The file QueryString.php exists in your SMF installation.
  3. Inspect IP detection logic in QueryString.php
    Open QueryString.php in a text editor and search for references to X-Forwarded-For. Look for code patterns where $_SERVER['HTTP_X_FORWARDED_FOR'] is being used as the primary or only source for determining the client IP address, without first checking $_SERVER['REMOTE_ADDR'].
    Affected if The code uses X-Forwarded-For as the primary IP source without first validating against REMOTE_ADDR.
  4. Verify if proxy handling is trusted
    Examine how the IP detection function handles multiple IPs in the X-Forwarded-For header. Check if the code simply trusts and uses the header value without validating that it comes from a trusted proxy, or if it only uses the first IP in a chain without sanitization.
    Affected if The code does not validate or sanitize the X-Forwarded-For header, or uses it unconditionally as a trusted source.

You are affected if your SMF version is 1.0.7 or earlier, or 1.1rc2 or earlier, AND your QueryString.php uses the X-Forwarded-For HTTP header as the primary source for client IP determination without proper validation against REMOTE_ADDR.

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
Upgrade available Upgrade to a release after 1.1_rc2
Interim mitigation

Modify QueryString.php to prioritize the REMOTE_ADDR server variable for IP detection and treat X-Forwarded-For only as an untrusted fallback with strict validation (e.g., only use the first IP in the chain, reject internal/IPv6 as needed). Implement proper IP ban enforcement using the validated IP.

Fix this in Simple Machines Forum Scoped from the published advisory
  • Consultation1.0 h
  • Implementation2.0 h
  • Testing3.0 h
  • Review / QA1.0 h
7.0 hours of engineering $1,190
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,904.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2006-7013 — 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 sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2006-7013 in production — separate from our analysis above.

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.

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