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OS Command InjectionWeakness · CWE-78

CVE-2026-44666

CRITICAL · 9.3 CVSS v4.0 Published 2026-05-14
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
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
HRConvert2 is a self-hosted, drag-and-drop & nosql file conversion server & share tool. Prior to 3.3.8, the sanitizeString() function in convertCore.php is missing backtick (`) and tab (\t) from its strip list. User input then reaches shell_exec(), where the shell interprets these characters and commands within filenames execute. This vulnerability is fixed in 3.3.8.

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

HRConvert2's sanitizeString() function in convertCore.php fails to strip backticks (`) and tab characters (\t) from user input before passing filenames to shell_exec(), enabling command injection via crafted filenames. This is a classic OS command injection vulnerability stemming from incomplete input sanitization.

MitigationUpgrade to HRConvert2 version 3.3.8 or later, which includes the corrected sanitizeString() function that strips backticks and tabs. If immediate upgrade is not feasible, implement input validation to reject filenames containing shell metacharacters before reaching shell_exec().

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
Authentication
X
User interaction
None
Scope
X

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:L/SI:L/SA:L/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

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. Locate HRConvert2 installation
    Search the web server filesystem for the convertCore.php file, typically found in the HRConvert2 application directory under /core/ or /includes/ paths.
    Affected if The file convertCore.php exists and belongs to the HRConvert2 application.
  2. Identify the HRConvert2 version
    Check for a version file (version.txt, README, or header comments in main PHP files) or inspect the convertCore.php file header for version metadata.
    Affected if The installed version is 3.3.7 or earlier (versions 3.3.8 and later contain the fix).
  3. Examine the sanitizeString function
    Open convertCore.php and locate the sanitizeString() function definition. Review its implementation to see if it explicitly filters or removes backtick (`) and tab (\t) characters.
    Affected if The function exists but does not filter backtick or tab characters from input strings.
  4. Verify shell_exec usage with user input
    Search convertCore.php for shell_exec() calls. Trace back to determine if user-supplied filenames (from $_GET, $_POST, or $_FILES) are passed to these calls without passing through sanitizeString() first.
    Affected if shell_exec() receives filenames directly from user input without sanitization.
  5. Confirm the vulnerability trigger point
    Identify the web endpoints or functions that accept filename uploads or parameters and pass them to shell_exec(). Common entry points include file conversion, extraction, or processing features.
    Affected if User-controlled filenames can reach shell_exec() without the backtick and tab characters being removed.

A system is affected if HRConvert2 version 3.3.7 or earlier is running and the sanitizeString() function in convertCore.php does not filter backtick and tab characters before passing filenames to shell_exec().

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
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Upgrade to HRConvert2 version 3.3.8 or later, which includes the corrected sanitizeString() function that strips backticks and tabs. If immediate upgrade is not feasible, implement input validation to reject filenames containing shell metacharacters before reaching shell_exec().

Recommended fix Moderate confidence

Upgrade to HRConvert2 version 3.3.8

  1. 1. Create a full backup of the current HRConvert2 installation including all uploaded files and configuration
  2. 2. Download HRConvert2 version 3.3.8 from the official GitHub repository
  3. 3. Replace the existing convertCore.php file with the version 3.3.8 file, or upgrade the entire application
  4. 4. Verify the sanitizeString() function in the new convertCore.php now properly strips backticks (`) and tab characters (\t)
  5. 5. Test file upload and conversion functionality to ensure normal operations work correctly
  6. 6. Verify the fix by attempting to use a filename containing backticks or tabs - it should be sanitized and not execute any commands
Caveat Review release notes for 3.3.8 to check for any breaking changes in functionality or configuration

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

Have this fixed Scoped from the published advisory
  • Consultation2.0 h
  • Implementation2.0 h
  • Testing4.0 h
  • Review / QA2.0 h
10.0 hours of engineering $1,720
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An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,752.

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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-2026-44666 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