Notes attachment render HTML in preview mode
Priority LOW 28CWE-79Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- Required
- Attack complexity
- Low
- Impact type
- Cross-site scripting
- Confidentiality · integrity · availability
- Low · Low · None
- Fix status
- Fixed
Attack profile from CVSS 3.1 · NVD. Fix status from CNA. Impact type from CWE-79.
Summary
Notes is a note-taking app for Nextcloud, an open-source cloud platform. Starting in version 4.4.0 and prior to version 4.8.0, when creating a note file with HTML, the content is rendered in the preview instead of the file being offered to download. Nextcloud Notes app version 4.8.0 contains a patch for the issue. No known workarounds are available.
Why it matters now
Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00588 48th percentileScored 2026-11-07
Fix Fixed security-advisories (nextcloud): 4.8.0
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
Remediation
- Fix · CNA security-advisories (nextcloud) Fixed in 4.8.0
Vendor assessments
Timeline
- 2026-10-02 Threatist record created from CVE-2023-39955
References
More nextcloud Notes vulnerabilities
- TI-2024-24829 Nextcloud Notes app can be tricked into using a received share created before the user logged in CVSS 3.1MEDIUM 4.6
Sources
- CVE-2023-39955 · CVE Program
- CVE-2023-39955 · NVD
- FIRST EPSS
- CVE-2023-39955 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences