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Stack-based Buffer OverflowWeakness · CWE-121

CVE-2020-36997

CRITICAL · 9.8 CVSS v3.1 Published 2026-01-29
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
100/100
Remediation priority · Urgent
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
BacklinkSpeed 2.4 contains a buffer overflow vulnerability that allows attackers to corrupt the Structured Exception Handler (SEH) chain through malicious file import. Attackers can craft a specially designed payload file to overwrite SEH addresses, potentially executing arbitrary code and gaining control of the application.

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

BacklinkSpeed 2.4 contains a buffer overflow in its file import functionality that allows attackers to corrupt the Windows Structured Exception Handler (SEH) chain. By crafting a specially designed payload file, an attacker can overwrite SEH addresses and achieve arbitrary code execution with full application control.

MitigationInput validation and bounds checking should be implemented during file parsing operations, with safe string handling functions replacing vulnerable ones. If the software is no longer maintained, consider migrating to a actively maintained alternative or implementing additional sandboxing/mitigation controls.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

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. Identify if BacklinkSpeed is installed
    Look for BacklinkSpeed in installed programs list (Windows: Add/Remove Programs, Programs and Features, or check common installation directories such as C:\Program Files\ or C:\Program Files (x86)\). Also search for executable files named backlinkspeed.exe or similar.
    Affected if BacklinkSpeed software is found on the system regardless of version status.
  2. Determine the installed version
    Right-click the BacklinkSpeed executable, select Properties, then check the Details tab for version information. Alternatively, open the application and look for About or Help menu options that display the version number.
    Affected if The installed version is BacklinkSpeed 2.4 specifically.
  3. Verify the file import functionality exists
    Launch BacklinkSpeed and navigate through the menu options to locate any file import, load file, or import data features. Look for menu items such as File > Import, File > Load, or similar options that handle external file loading.
    Affected if The file import feature is present and accessible in the application.
  4. Inspect for suspicious payload files
    Search the system for recently created or modified files with extensions that may be used as payload vectors (such as .txt, .csv, .dat, or custom file formats). Check download folders, temporary directories, and the BacklinkSpeed working directory.
    Affected if Unexpected or unknown files are found that may have been used as crafted payload files for import.
  5. Review application crash logs or event logs
    Check Windows Event Viewer for application crash events related to BacklinkSpeed. Also check for any .dmp (dump) files or crash reports in the BacklinkSpeed installation directory or Windows crash dump locations.
    Affected if Crash events or dump files exist that indicate SEH corruption or buffer overflow symptoms.

A system is affected if BacklinkSpeed version 2.4 is installed and the file import functionality is accessible or has been used with untrusted files.

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

Input validation and bounds checking should be implemented during file parsing operations, with safe string handling functions replacing vulnerable ones. If the software is no longer maintained, consider migrating to a actively maintained alternative or implementing additional sandboxing/mitigation controls.

Have this fixed Scoped from the published advisory
  • Consultation3.0 h
  • Implementation6.0 h
  • Testing3.0 h
  • Review / QA2.0 h
14.0 hours of engineering $2,490
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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-2020-36997 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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