Medium 6.1Published Sep 24, 2026

CVE-2026-93405Mailspring: Stored XSS in attachment quick preview (unsanitized Markdown/DOCX/XLSX conversion)

Updated under an hour ago (2026-10-19 06:25 UTC)

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It affects Foundry376 Mailspring. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

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Every CVE for Foundry376 Mailspring

Exploited in the last 30 days

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: 6.1 MEDIUM (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
Weakness (CWE): CWE-79
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: GitHub_M
NVD analysis: Deferred
Record last updated: Sep 29, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

Foundry376 Mailspring foundry376:mailspring (from the name)	before 1.17.0	CNA record

References

https://github.com/Foundry376/Mailspring/security/advisories/GHSA-px2g-jhg5-c6ghx-refsource-confirm
https://github.com/Foundry376/Mailspring/pull/2523x-refsource-misc
https://github.com/Foundry376/Mailspring/commit/5728388199666ec0a9a58f693c89c25b948a9b6cx-refsource-misc
https://github.com/Foundry376/Mailspring/releases/tag/1.17.0x-refsource-misc

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.