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Actively exploited in the wild. This CVE is on the CISA Known Exploited Vulnerabilities list — treat remediation as urgent. Federal remediation due by 28 Jul 2025.
Multi Router Looking GlassApplication · Multi Router Looking Glass Project

CVE-2014-3931

CRITICAL · 9.8 CVSS v3.1 Published 2017-03-31
Fix available
A fix is available. Upgrade to after 5.4.1 or later.
See remediation →
100/100
Remediation priority · Urgent
In the wild Public exploit 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
fastping.c in MRLG (aka Multi-Router Looking Glass) before 5.5.0 allows remote attackers to cause an arbitrary memory write and memory corruption.

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 · moderate confidence

A memory corruption vulnerability exists in fastping.c within the Multi-Router Looking Glass (MRLG) application versions prior to 5.5.0. The flaw allows remote attackers to perform arbitrary memory writes, leading to memory corruption. This critical issue in the ICMP ping functionality could potentially enable remote code execution given the arbitrary write primitive.

MitigationUpgrade MRLG to version 5.5.0 or later to obtain the patch. If immediate upgrade is not feasible, restrict network access to the MRLG service to trusted sources only to reduce attack surface.

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
Multi Router Looking GlassApplication
Affected:<= 5.4.1

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

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

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. Confirm MRLG is installed
    Look for MRLG (Multi Router Looking Glass) web interface or service on the system. Check for files named 'mrlg', 'looking glass', or related web application files in web server directories.
    Affected if MRLG software is present on the system
  2. Identify the installed MRLG version
    Check the application's version information, typically found in the web interface footer, an 'about' page, or in version files within the MRLG installation directory.
    Affected if The installed version cannot be determined or is 5.4.1 or earlier
  3. Compare version to affected range
    Review the identified version number against the affected range: any version 5.4.1 or earlier is vulnerable. Versions 5.5.0 and later are patched.
    Affected if Installed version is 5.4.1 or lower, indicating the vulnerable version range
  4. Check if remote network access is enabled
    Verify if the MRLG web interface is exposed to network access, as the vulnerability allows remote arbitrary memory writes.
    Affected if MRLG is reachable from untrusted networks (not limited to localhost or protected internal networks)

If MRLG is installed and the version is 5.4.1 or earlier with network exposure, the system is affected by CVE-2014-3931.

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 a release after 5.4.1
Interim mitigation

Upgrade MRLG to version 5.5.0 or later to obtain the patch. If immediate upgrade is not feasible, restrict network access to the MRLG service to trusted sources only to reduce attack surface.

Recommended fix High confidence

5.5.0 or later

  1. 1. Identify the current MRLG version by checking the application or documentation
  2. 2. Create a full backup of the MRLG configuration and any associated data
  3. 3. Download MRLG version 5.5.0 or later from the official source (mrlg.op-sec.us or authorized distribution point)
  4. 4. Install the upgraded version following the standard installation procedure for MRLG
  5. 5. Restore the backed-up configuration to the new installation
  6. 6. Verify that the fastping.c component has been updated and the service is functioning correctly

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

Fix this in Multi Router Looking Glass Exploited in the wild — priority engagement
  • Consultation2.0 h
  • Implementation1.0 h
  • Testing2.0 h
  • Review / QA1.0 h
6.0 hours of engineering $1,060
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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-2014-3931 in production — separate from our analysis above.

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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