CVE-2026-42090

CRITICALNVD 9.69.6
EchelonGraph scoreMEDIUM confidence

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

This critical-severity CVE scores 9.6 under NVD CVSS v3. EPSS exploit probability: 0.8% (57th percentile of EPSS-scored CVEs). No GitHub Security Advisory CVSS is on record for this CVE.

Triggered by: Headline CVSS from NVD CVSS v3
Sources: EPSS, NVD CVSS v3
9.6EG
EchelonGraph verdictPlan a fixRemediate within your standard update timelines (the SSVC decision on this page).
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.8%CVSS: 9.6Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

Notesnook is a note-taking app focused on user privacy & ease of use. Prior to Notesnook Web/Desktop version 3.3.15 and prior to Notesnook iOS/Android version 3.3.20, a stored XSS vulnerability in the note export flow can be escalated to remote code execution in the desktop app. The root cause is that exported note fields such as title, headline, and content are inserted into the generated HTML template without HTML escaping. When the note is later exported to PDF, Notesnook renders that HTML into a same-origin, unsandboxed iframe using iframe.srcdoc = .... Injected script executes in the Notesnook origin. In the desktop app, this becomes RCE because Electron is configured with nodeIntegration: true and contextIsolation: false. This issue has been patched in Notesnook Web/Desktop version 3.3.15 and Notesnook iOS/Android version 3.3.20.

CVSS v3
9.6
EG Score
9.6CRITICALmedium confidence
EG Risk
44
EG Risk 44/100

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed (value × EchelonGraph’s weight)
Severity96% × 45%
The EG Score, 9.6 of 10.
Exploitation0.9% × 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 low or medium mission impact; Track* at high (mission-essential systems).
Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact total (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
0.8%
EPSS %ILE
57th
KEV
Not listed

SSVC (CISA's decision table, applied by EchelonGraph)Track at low or medium mission impact; Track* at high (mission-essential systems).

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

Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact total (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)14 days if the affected system is publicly exposed; Fix on system upgrade if it is not.

In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA Vulnrichment) · Technical impact total (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

May 4, 2026

Last Modified

May 12, 2026

Advisory Details (3)

Auto-updated Oct 2, 2026
Patch available. Sources: github_release, github.
GitHub advisoryMentions a patch (unverified)

RCE via stored XSS in note export rendering · Advisory · streetwriters/notesnook · GitHub

https://github.com/streetwriters/notesnook/security/advisories/GHSA-fjm8-jg78-89h4
GitHub release Patch Available

Notesnook Desktop v3.3.15

Patch available: streetwriters/notesnook v3.3.15

https://github.com/streetwriters/notesnook/releases/tag/v3.3.15
GitHub release Patch Available

Notesnook Android v3.3.20

Patch available: streetwriters/notesnook 3.3.20-android

https://github.com/streetwriters/notesnook/releases/tag/3.3.20-android

Weakness Classification(2)

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

Data Freshness Timeline

(refreshed 15× in last 7d / 31× 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.

Showing the most recent 99 of 185 refreshes on record for this CVE.

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 100 is merged into the row it repeats. The 86 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-10-16 16:42 UTCEPSS rescoreEPSS 0.8% · 57th percentile
  2. 2026-10-16 12:30 UTCEG score recompute
  3. 2026-10-15 16:32 UTCEPSS rescoreEPSS 0.8% · 57th percentile
  4. 2026-10-15 14:18 UTCEG score recompute
  5. 2026-10-14 16:33 UTCEPSS rescoreEPSS 0.8% · 57th percentile
  6. 2026-10-14 09:02 UTCEG score recompute
  7. 2026-10-13 16:34 UTCEPSS rescoreEPSS 0.8% · 57th percentile
  8. 2026-10-13 05:47 UTCEG score recompute
  9. 2026-10-12 16:34 UTCEPSS rescoreEPSS 0.8% · 56th percentile
  10. 2026-10-12 16:07 UTCEG score recompute
  11. 2026-10-11 19:49 UTCEG score recompute
  12. 2026-10-11 17:03 UTCEG score recompute
  13. 2026-10-11 14:29 UTCEG score recompute
  14. 2026-10-11 13:48 UTCEPSS rescoreEPSS 0.8% · 56th percentile
  15. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.8% · 56th percentile
  16. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.8% · 56th percentile
  17. 2026-10-08 17:12 UTCEPSS rescoreEPSS 0.8% · 56th percentile
  18. 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.8% · 56th percentile
  19. 2026-10-06 15:17 UTCEPSS rescoreEPSS 0.8% · 56th percentile
  20. 2026-10-05 17:43 UTCEPSS rescoreEPSS 0.8% · 56th percentile
  21. 2026-10-04 23:22 UTCEPSS rescoreEPSS 0.8% · 56th percentile
  22. 2026-10-03 14:25 UTCEPSS rescoreEPSS 0.8% · 56th percentile
  23. 2026-10-01 19:50 UTCEPSS rescoreEPSS 0.8% · 56th percentile
  24. 2026-09-30 15:03 UTCEPSS rescoreEPSS 0.8% · 56th percentile
  25. 2026-09-30 11:17 UTCOSV refresh
Show 74 more
  1. 2026-09-27 13:48 UTCEPSS rescoreEPSS 0.8% · 56th percentile
  2. 2026-09-26 15:58 UTCEPSS rescoreEPSS 0.8% · 56th percentile
  3. 2026-09-23 17:53 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  4. 2026-09-20 20:15 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  5. 2026-09-18 19:28 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  6. 2026-09-17 19:31 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  7. 2026-09-16 14:08 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  8. 2026-09-16 05:15 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  9. 2026-09-13 16:47 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  10. 2026-09-12 15:01 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  11. 2026-09-11 18:10 UTCOSV refresh
  12. 2026-09-11 14:53 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  13. 2026-09-11 09:37 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  14. 2026-09-10 09:34 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  15. 2026-09-08 22:00 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  16. 2026-09-07 16:01 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  17. 2026-09-06 13:47 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  18. 2026-09-04 05:06 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  19. 2026-09-02 14:12 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  20. 2026-09-01 13:54 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  21. 2026-09-01 04:39 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  22. 2026-08-30 19:17 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  23. 2026-08-30 01:22 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  24. 2026-08-28 21:41 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  25. 2026-08-27 14:25 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  26. 2026-08-26 14:46 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  27. 2026-08-25 13:49 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  28. 2026-08-23 21:33 UTCEG score recompute
  29. 2026-08-23 00:19 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  30. 2026-08-21 23:49 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  31. 2026-08-20 22:55 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  32. 2026-08-19 17:03 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  33. 2026-08-18 13:48 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  34. 2026-08-17 13:47 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  35. 2026-08-17 13:12 UTCEG score recompute
  36. 2026-08-16 14:56 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  37. 2026-08-16 05:03 UTCEG score recompute
  38. 2026-08-16 02:14 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  39. 2026-08-15 02:11 UTCEG score recompute
  40. 2026-08-15 01:30 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  41. 2026-08-14 03:38 UTCEG score recompute
  42. 2026-08-13 22:00 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  43. 2026-08-12 17:16 UTCEG score recompute
  44. 2026-08-12 13:51 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  45. 2026-08-11 16:09 UTCEG score recompute
  46. 2026-08-11 13:43 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  47. 2026-08-11 01:40 UTCEG score recompute
  48. 2026-08-11 00:00 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  49. 2026-08-09 14:15 UTCEG score recompute
  50. 2026-08-09 13:46 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  51. 2026-08-09 02:45 UTCEG score recompute
  52. 2026-08-08 16:37 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  53. 2026-08-07 18:52 UTCEG score recompute
  54. 2026-08-06 17:11 UTCEG score recompute
  55. 2026-08-06 13:46 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  56. 2026-08-05 22:29 UTCEG score recompute
  57. 2026-08-05 19:17 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  58. 2026-08-04 15:10 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  59. 2026-08-04 10:38 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  60. 2026-08-03 20:02 UTCEG score recompute
  61. 2026-08-03 10:36 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  62. 2026-08-02 05:28 UTCEG score recompute
  63. 2026-08-02 02:27 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  64. 2026-08-01 04:16 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  65. 2026-07-30 16:28 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  66. 2026-07-30 01:30 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  67. 2026-07-28 15:36 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  68. 2026-07-27 14:13 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  69. 2026-07-26 14:54 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  70. 2026-07-25 14:18 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  71. 2026-07-24 14:17 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  72. 2026-07-23 14:18 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  73. 2026-07-23 03:11 UTCEG score recompute
  74. 2026-07-22 14:08 UTCEPSS rescoreEPSS 0.5% · 38th percentile

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Frequently asked(5)

What is CVE-2026-42090?
CVE-2026-42090 is a critical-severity vulnerability; its CVE record was published on May 4, 2026. Notesnook is a note-taking app focused on user privacy & ease of use. Prior to Notesnook Web/Desktop version 3.3.15 and prior to Notesnook iOS/Android version 3.3.20, a stored XSS vulnerability in the note export flow can be escalated to remote code execution in the desktop app. The root cause is…
When was the CVE record for CVE-2026-42090 published?
The CVE record for CVE-2026-42090 was published on May 4, 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 May 12, 2026; the record at its source may have been updated since.
Is CVE-2026-42090 actively exploited?
CVE-2026-42090 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.8% probability of exploitation in the next 30 days (57th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-42090?
CVE-2026-42090 has a CVSS v3 base score of 9.6 (NVD).
How do I remediate CVE-2026-42090?
A fix for CVE-2026-42090 is available: update to the fixed version the vendor names in its advisory.

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