Security readout for executives and security teams
Plain-English summary
CVE-2022-39331 lets a logged-in attacker inject HTML into notifications shown by the Nextcloud Desktop Client. The documented impact is limited loss of confidentiality and integrity, not service disruption. The vendor recommends upgrading the Desktop Client to 3.6.1, with no known workaround.
Executive priority
Handle through normal vulnerability remediation cycles, with emphasis on endpoint inventory. This is not evidenced as actively exploited, but the fix is clear and affected desktop clients can expose users to notification-based content injection.
Technical view
This is a CWE-79 cross-site scripting issue in Nextcloud Desktop Client notifications before 3.6.1. The CVSS 3.1 vector is AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:L/A:N, meaning exploitation requires attacker privileges and user interaction, with limited confidentiality and integrity impact.
Likely exposure
Organizations are exposed where Nextcloud Desktop Client versions earlier than 3.6.1 remain installed. Exposure is client-side, tied to notification handling in the desktop sync application, not a server-side Nextcloud instance by itself.
Exploitation context
The bundle does not show CISA KEV listing or active exploitation evidence. A public HackerOne report and vendor advisory exist, so defenders should treat technical details as public while avoiding claims of in-the-wild exploitation.
Researcher notes
Focus validation on client version and notification-rendering exposure. The source bundle attributes the issue to arbitrary HTML injection in desktop notifications and identifies 3.6.1 as the recommended upgrade. No workaround or active exploitation evidence is provided.
Mitigation direction
- Upgrade Nextcloud Desktop Client to version 3.6.1 or later.
- Prioritize managed endpoints with older desktop sync clients installed.
- Check vendor and distribution advisories for package-specific update guidance.
- Do not rely on compensating workarounds; none are named in the sources.
Validation and detection
- Inventory installed Nextcloud Desktop Client versions across managed endpoints.
- Confirm every deployed client reports version 3.6.1 or later.
- Review endpoint software/package records for CVE-2022-39331 references.
- Check Debian LTS guidance if using distribution-provided packages.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-79: User-session and phishing behavior lookup
Client-side and session-facing weaknesses should be reviewed alongside initial-access and user-execution behaviors. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCVE-2022-39331 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Medium
- CVSS
- 4.6 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:L/A:N
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:L/A:N2.12.5Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
4.6MediumVector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:L/A:N
Source materials
- CVE List V5 sourceCVE List V5
- https://github.com/nextcloud/security-advisories/security/advisories/GHSA-c3xh-q694-6rc5CVE reference
- https://github.com/nextcloud/desktop/pull/4944CVE reference
- https://hackerone.com/reports/1668028CVE reference
- https://lists.debian.org/debian-lts-announce/2025/09/msg00018.htmlCVE reference
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.