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.
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Fixes
Solution
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Workaround
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References
History
Thu, 24 Sep 2026 18:15:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| 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. | |
| Title | Mailspring: Stored XSS in attachment quick preview (unsanitized Markdown/DOCX/XLSX conversion) | |
| Weaknesses | CWE-79 | |
| References |
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| Metrics |
cvssV3_1
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Projects
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Status: PUBLISHED
Assigner: GitHub_M
Published:
Updated: 2026-09-24T18:00:32.245Z
Reserved: 2026-09-17T20:57:18.983Z
Link: CVE-2026-93405
No data.
Status : Received
Published: 2026-09-24T18:19:07.120
Modified: 2026-09-24T18:19:07.120
Link: CVE-2026-93405
No data.
OpenCVE Enrichment
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Weaknesses