CVE-2026-42090

CRITICALNVD 9.69.6—
EchelonGraph scoreMEDIUM confidence

This critical-severity CVE scores 9.6 under NVD CVSS v3. EPSS exploit probability: 0.2%, top 59% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, nvd
9.6
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 0%CVSS: 9.6Exploit: NoneExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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
9.6(medium)
EPSS
38.1%
KEV
Not listed

Published

May 4, 2026

Last Modified

May 12, 2026

Advisory Details (3)

Auto-updated May 4, 2026
🔬 Proof of concept available. Patch available. Sources: github.
github Patch Available🟡 PoC Available

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

https://github.com/streetwriters/notesnook/security/advisories/GHSA-fjm8-jg78-89h4
generic

Release Notesnook Desktop v3.3.15 · streetwriters/notesnook · GitHub

https://github.com/streetwriters/notesnook/releases/tag/v3.3.15
generic

Release Notesnook Android v3.3.20 · streetwriters/notesnook · GitHub

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 8× in last 7d / 36× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. 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. Most recent first.

Showing the most recent 100 of 155 total refreshes for this CVE.

  1. 2026-07-16 17:03 UTCEPSS rescore
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Frequently asked(5)

What is CVE-2026-42090?
CVE-2026-42090 is a critical vulnerability 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 CVE-2026-42090 disclosed?
CVE-2026-42090 was first published in the National Vulnerability Database on May 4, 2026, with the most recent update on May 12, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-42090 actively exploited?
CVE-2026-42090 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 38.1% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
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?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-42090, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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