CVE-2026-93405

MEDIUMPre-NVD 6.16.1
EchelonGraph scoreMEDIUM confidence

“—” beside the score: it is equal to the CVSS score beside it.

This medium-severity CVE scores 6.1 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.2% (13th percentile of EPSS-scored CVEs). No GitHub Security Advisory CVSS is on record for this CVE.

Triggered by: Headline CVSS from a secondary CVSS source
Sources: EPSS, a secondary CVSS source

Also known asEUVD-2026-86337 (ENISA EUVD)Source: ENISA EUVD

6.1EG
EchelonGraph verdictMonitorRemediate within your standard update timelines (the SSVC decision on this page).
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0.2%CVSS: 6.1Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

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
6.1
EG Score
6.1MEDIUMmedium confidence
EG Risk
28
EG Risk 28/100

EG Risk is EchelonGraph's 0–100 priority score. It fuses impact severity (EG Severity, the CVSS base score, never the KEV-floored or EPSS-lifted EG Score) with real-world exploitation and automatability, under weights EchelonGraph set by hand, so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner.

How it’s computed (value × EchelonGraph’s weight)
Severity61% × 45%
Impact severity (EG Severity): CVSS 6.1 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation0.2% × 40%
FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.
Automatability0% × 15%
CISA's SSVC Automatable value: no (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at every mission impact level.
Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.
Action: A fix is available. Apply it within your standard update timelines.
EPSS PROB
0.2%
EPSS %ILE
13th
KEV
Not listed

What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)

The EG score (6.1): severity, escalated by confirmed exploitation. This CVE's 6.1 is its impact severity (EG Severity), not escalated.

EG Severity
6.1 MEDIUMCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.a secondary CVSS source · CVSS v3.0 or v3.1
EG Likelihood
0.2% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-24). FIRST's exploitation probability, not an EchelonGraph model.
Confirmed exploitation
None on record (CISA KEV, EG-KEV Tier 1)Reported apart from the likelihood: an observed fact, not a probability.
EG Priority
SSVC Track at medium mission impactTrack at every mission impact level.CISA BOD 26-04: 60 days if the affected system is publicly exposed; Fix on system upgrade if it is not.Each input and its source, and whom BOD 26-04 binds: the SSVC and BOD 26-04 blocks below.

SSVC (CISA's decision table, applied by EchelonGraph)Track at every mission impact level.

A fix is available. Apply it within your standard update timelines.

Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table

BOD 26-04 (CISA's remediation timeline, Table 1)60 days if the affected system is publicly exposed; Fix on system upgrade if it is not.

The score's inputs: In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it

Published

September 24, 2026

Last Modified

September 30, 2026

Advisory Details (4)

Auto-updated Sep 24, 2026
Patch available. Sources: github_commit, github_release, github, github_pr.
GitHub release Patch Available

1.17.0

Patch available: Foundry376/Mailspring 1.17.0

https://github.com/Foundry376/Mailspring/releases/tag/1.17.0
GitHub commit

commit 572838819966 (Foundry376/Mailspring)

Fix landed in Foundry376/Mailspring commit 572838819966 — awaiting tagged release

https://github.com/Foundry376/Mailspring/commit/5728388199666ec0a9a58f693c89c25b948a9b6c
GitHub pull request

Add additional safeguards to attachment preview generation

Fix merged in Foundry376/Mailspring PR #2523 on 2026-01-02 — awaiting tagged release

https://github.com/Foundry376/Mailspring/pull/2523
GitHub advisoryMentions a patch (unverified)

Stored XSS in Mailspring attachment quick preview (unsanitized Markdown/DOCX/XLSX conversion) · Advisory · Foundry376/Mailspring · GitHub

https://github.com/Foundry376/Mailspring/security/advisories/GHSA-px2g-jhg5-c6gh

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 8× in last 7d / 44× in last 30d)

Each row is a time one of our pipelines fetched, updated or re-scored this CVE. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). Most recent first.

A repeat, a row identical to one the same pipeline wrote less than 10 seconds earlier, is not a separate refresh and is not counted. 1 repeat row among the latest 63 is merged into the row it repeats.

  1. 2026-11-02 16:46 UTCEPSS rescoreEPSS 0.2% · 13th percentile
  2. 2026-11-01 16:36 UTCEPSS rescoreEPSS 0.2% · 13th percentile
  3. 2026-10-31 16:33 UTCEPSS rescoreEPSS 0.2% · 13th percentile
  4. 2026-10-30 16:35 UTCEPSS rescoreEPSS 0.2% · 13th percentile
  5. 2026-10-29 21:55 UTCOSV refresh
  6. 2026-10-29 16:34 UTCEPSS rescoreEPSS 0.2% · 13th percentile
  7. 2026-10-28 16:33 UTCEPSS rescoreEPSS 0.2% · 13th percentile
  8. 2026-10-27 16:33 UTCEPSS rescoreEPSS 0.2% · 13th percentile
  9. 2026-10-26 16:33 UTCEPSS rescoreEPSS 0.2% · 13th percentile
  10. 2026-10-25 16:34 UTCEPSS rescoreEPSS 0.2% · 13th percentile
  11. 2026-10-25 13:49 UTCEG score recompute
  12. 2026-10-24 16:34 UTCEPSS rescoreEPSS 0.2% · 12th percentile
  13. 2026-10-23 16:33 UTCEPSS rescoreEPSS 0.2% · 12th percentile
  14. 2026-10-22 16:35 UTCEPSS rescoreEPSS 0.2% · 12th percentile
  15. 2026-10-22 12:29 UTCEG score recompute
  16. 2026-10-21 16:34 UTCEPSS rescoreEPSS 0.2% · 12th percentile
  17. 2026-10-20 16:34 UTCEPSS rescoreEPSS 0.2% · 12th percentile
  18. 2026-10-19 16:33 UTCEPSS rescoreEPSS 0.2% · 12th percentile
  19. 2026-10-18 02:59 UTCEG score recompute
  20. 2026-10-17 16:35 UTCEPSS rescoreEPSS 0.2% · 12th percentile
  21. 2026-10-16 16:45 UTCEPSS rescoreEPSS 0.2% · 12th percentile
  22. 2026-10-15 16:33 UTCEPSS rescoreEPSS 0.2% · 12th percentile
  23. 2026-10-14 16:34 UTCEPSS rescoreEPSS 0.2% · 12th percentile
  24. 2026-10-13 16:35 UTCEPSS rescoreEPSS 0.2% · 12th percentile
  25. 2026-10-12 14:43 UTCEG score recompute
Show 37 more
  1. 2026-10-11 19:12 UTCEG score recompute
  2. 2026-10-11 16:28 UTCEG score recompute
  3. 2026-10-11 16:02 UTCEG score recompute
  4. 2026-10-11 13:50 UTCEPSS rescoreEPSS 0.2% · 12th percentile
  5. 2026-10-11 13:42 UTCEG score recompute
  6. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.2% · 12th percentile
  7. 2026-10-10 14:18 UTCEG score recompute
  8. 2026-10-09 20:08 UTCEPSS rescoreEPSS 0.2% · 12th percentile
  9. 2026-10-09 12:29 UTCEG score recompute
  10. 2026-10-08 17:14 UTCEPSS rescoreEPSS 0.2% · 12th percentile
  11. 2026-10-08 08:26 UTCEG score recompute
  12. 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.2% · 12th percentile
  13. 2026-10-07 06:41 UTCEG score recompute
  14. 2026-10-06 15:19 UTCEPSS rescoreEPSS 0.2% · 12th percentile
  15. 2026-10-06 04:56 UTCEG score recompute
  16. 2026-10-05 17:44 UTCEPSS rescoreEPSS 0.2% · 12th percentile
  17. 2026-10-05 03:11 UTCEG score recompute
  18. 2026-10-04 23:23 UTCEPSS rescoreEPSS 0.2% · 12th percentile
  19. 2026-10-04 01:27 UTCEG score recompute
  20. 2026-10-03 14:26 UTCEPSS rescoreEPSS 0.2% · 12th percentile
  21. 2026-10-02 23:38 UTCEG score recompute
  22. 2026-10-01 21:53 UTCEG score recompute
  23. 2026-10-01 19:51 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  24. 2026-09-30 20:02 UTCEG score recompute
  25. 2026-09-30 15:04 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  26. 2026-09-30 06:16 UTCEG score recompute
  27. 2026-09-29 04:32 UTCEG score recompute
  28. 2026-09-29 03:21 UTCEG score recompute
  29. 2026-09-29 01:34 UTCEG score recompute
  30. 2026-09-28 13:52 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  31. 2026-09-27 23:50 UTCEG score recompute
  32. 2026-09-27 13:49 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  33. 2026-09-26 22:05 UTCEG score recompute
  34. 2026-09-26 15:59 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  35. 2026-09-24 18:35 UTCEG score recompute
  36. 2026-09-24 18:02 UTCEG score recomputeFirst assessed: 6.1 MEDIUM
  37. 2026-09-24 18:01 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-93405?
CVE-2026-93405 is a medium-severity vulnerability; its CVE record was published on September 24, 2026. 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…
When was the CVE record for CVE-2026-93405 published?
The CVE record for CVE-2026-93405 was published on September 24, 2026. That is the record's publication date; the vulnerability itself may have been made public earlier. EchelonGraph's copy of the record carries a last-modified date of September 30, 2026; the record at its source may have been updated since.
Is CVE-2026-93405 actively exploited?
CVE-2026-93405 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.2% probability of exploitation in the next 30 days (13th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-93405?
CVE-2026-93405 has a CVSS base score of 6.1 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-93405?
A fix for CVE-2026-93405 is available: update to the fixed version the vendor names in its advisory.

Dependency Blast Radius

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