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Vulnerabilities

Vulnerability · CVE-2026-40262

Note Mark is an open-source note-taking application.

Published Apr 17, 2026 · catalog updated Jun 17, 2026 · Note Mark is an

Check if you run it

No confirmed exploitation is on record for CVE-2026-40262. EPSS is 0.42%. Act only if a listed version of Note Mark is an is installed.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (Note Mark is an).
  • No version range is stored. A customer cannot check an installed version against this record.
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
High8.7
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.42%
Remediation
Advisory link
Affected products
See sources for product scope

Note Mark is an open-source note-taking application. In versions 0.19.1 and prior, the asset delivery handler serves uploaded files inline and relies on magic-byte detection for content type, which does not identify text-based formats such as HTML, SVG, or XHTML. These files are served with an empty Content-Type, no X-Content-Type-Options: nosniff header, and inline disposition, allowing browsers to sniff and render active content. An authenticated user can upload an HTML or SVG file containing JavaScript as a note asset, and when a victim navigates to the asset URL, the script executes under the application's origin with access to the victim's authenticated session and API actions. This issue has been fixed in version 0.19.2.

No affected version ranges are stored yet. Use the vendor advisory before you decide this record does not apply.

How to fix CVE-2026-40262

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-40262. EPSS is 0.42%. Act only if a listed version of Note Mark is an is installed.

Which versions are affected?

Affected version ranges are not on this record. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-434: Unrestricted Upload of File with Dangerous Type; CWE-79: Cross-site Scripting (XSS). EPSS 0.42%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Apr 17, 2026 · NIST NVD

    Detected

    Note Mark is an open-source note-taking application. In versions 0.19.1 and prior, the asset delivery handler serves uploaded files inline and relies on magic-byte detection for content type, which does not identify text-based formats such as HTML, SVG, or XHTML. These files are served with an empty Content-Type, no X-Content-Type-Options: nosniff header, and inline disposition, allowing browsers

  2. Jun 17, 2026 · NIST NVD

    Updated

    Note Mark is an open-source note-taking application. In versions 0.19.1 and prior, the asset delivery handler serves uploaded files inline and relies on magic-byte detection for content type, which does not identify text-based formats such as HTML, SVG, or XHTML. These files are served with an empty Content-Type, no X-Content-Type-Options: nosniff header, and inline disposition, allowing browsers

Sources

  • CVE.orgVulnerability recordCVE-2026-40262

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-40262

    30-day exploitation probability 0.4%

    first.org
  • NIST NVDVulnerability recordCVE-2026-40262

    Note Mark is an open-source note-taking application. In versions 0.19.1 and prior, the asset delivery handler serves uploaded files inline and relies on magic-byte detection for content type, which does not identify text-based formats such as HTML, SVG, or XHTML. These files are

    nvd.nist.gov

References

Freshness

Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.