CVE-2026-93405: CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') in Foundry376 Mailspring
Mailspring is a fast, cross-platform, open-source email client. Prior to 1.17.0, attachment quick preview converts Markdown, DOCX, and XLSX attachments with Snarkdown, Mammoth, and SheetJS and inserts the resulting HTML into the preview document through innerHTML without sanitization. A remote sender can craft a supported attachment whose converted HTML executes script when a recipient opens quick preview. The preview renderer has no direct Node or Electron access, but injected script can reach the IPC surface exposed to the quick-preview renderer. This issue alone provides script execution in the preview renderer; separate path-traversal and renderer-controlled file-write vulnerabilities are required for the documented persistent code-execution chain. This issue is fixed in version 1.17.0.
CVE-2026-93405: CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') in Foundry376 Mailspring
Description
Mailspring is a fast, cross-platform, open-source email client. Prior to 1.17.0, attachment quick preview converts Markdown, DOCX, and XLSX attachments with Snarkdown, Mammoth, and SheetJS and inserts the resulting HTML into the preview document through innerHTML without sanitization. A remote sender can craft a supported attachment whose converted HTML executes script when a recipient opens quick preview. The preview renderer has no direct Node or Electron access, but injected script can reach the IPC surface exposed to the quick-preview renderer. This issue alone provides script execution in the preview renderer; separate path-traversal and renderer-controlled file-write vulnerabilities are required for the documented persistent code-execution chain. This issue is fixed in version 1.17.0.
CVSS v3.1
Score 6.1medium
Affected software
Foundry376
Mailspring
Weaknesses
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-09-17T20:57:18.983Z
- Cvss Version
- 3.1
- State
- PUBLISHED
Threat ID: 6ab5661ef7a7c54106a606a7
Added to database: 09/24/2026, 18:04:14 UTC
Last updated: 09/24/2026, 18:04:14 UTC
Views: 1
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