CVE-2026-33978Public exploitNetwork attack vector

Stored XSS via unescaped web clip title

Published Apr 1, 2026 · Updated Apr 1, 2026

Stored XSS in Streetwriters Notesnook before 3.3.17 allows remote attackers to run script in the mobile share editor via crafted clip metadata. The sanitizeHtml function in apps/mobile/app/share/share.tsx inserts an unescaped title into an anchor, and the editor assigns the resulting string to innerHTML. Exploitation requires a victim to share attacker-controlled metadata to Notesnook and select Web clip on Android or iOS, after which the injected script runs in the share editor WebView context.

CVSS severity5.4
Medium
EPSS probability0.29%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stored XSS in Streetwriters Notesnook before 3.3.17 allows remote attackers to run script in the mobile share editor via crafted clip metadata. The sanitizeHtml function in apps/mobile/app/share/share.tsx inserts an unescaped title into an anchor, and the editor assigns the resulting string to innerHTML. Exploitation requires a victim to share attacker-controlled metadata to Notesnook and select Web clip on Android or iOS, after which the injected script runs in the share editor WebView context.

The record

CVE
CVE-2026-33978
Published
Apr 1, 2026
Updated
Apr 1, 2026
Vendor
Streetwriters
Product
Notesnook
Classifications
CWE-79, T1658
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 1, 2026CVE publishedPublication date reported by the CVE source.
  2. Apr 1, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 3.3.17

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Streetwriters · Notesnookversion=< 3.3.17

Published CVSS scores

6.1NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
5.4GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1658Exploitation for Client Execution

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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