Is CVE-2026-33978 in the CISA KEV catalog?

No. CVE-2026-33978 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2026-33978?

CVE-2026-33978 has a CVSS v3 base score of 5.4 (MEDIUM).

What is the EPSS score for CVE-2026-33978?

CVE-2026-33978 has an EPSS score of 0.29% (20th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2026-33978?

Upgrade notesnook mobile to 3.3.17 or later.

CVE & CISA-KEV Catalog

CVE-2026-33978

MEDIUM

5.4

CVSS v3

NVD

Description

Notesnook is a note-taking app focused on user privacy & ease of use. Prior to version 3.3.17, a stored XSS vulnerability exists in the mobile share / web clip flow because attacker-controlled clip metadata is concatenated into HTML without escaping and then rendered with innerHTML inside the mobile share editor WebView. An attacker can control the shared title metadata (for example through Android/iOS share metadata such as TITLE / SUBJECT, or through link-preview title data) and inject HTML such as . When the victim opens the Notesnook share flow and selects Web clip, the payload is inserted into the generated HTML and executed in the mobile editor WebView. This issue has been patched in version 3.3.17.

CWE-79Cross-Site Scripting (XSS)

How to fix

Remediation Available

notesnook mobileNVD

Affected:< 3.3.17Fixed in:3.3.17CVE-2026-33978derived from NVD

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredNone

User InteractionRequired

ScopeUnchanged

Impact

ConfidentialityLow

IntegrityLow

AvailabilityNone

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N

Exploit Intelligence

0.29%probability of exploitation in 30 days

20thpercentile

Low risk: more likely to be exploited than 20% of all known CVEs.

References

Patch1

github.com

Exploit1

github.com

Release Notes1

github.com

Related Vulnerabilities

Other CWE-79 (Cross-Site Scripting (XSS)) vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2020-11022	Medium	6.9	99%	-	Fix
CVE-2019-3929	Critical	9.8	99%	KEV	Fix
CVE-2020-9496	Medium	6.1	99%	-	-
CVE-2023-28341	Medium	6.1	99%	-	Fix
CVE-2018-12998	Medium	6.1	98%	-	-
CVE-2025-4123	High	7.6	98%	-	Fix

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Markdown

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-04-21.