# CVE-2018-3764: Cross-site scripting in Nextcloud Contacts application

> Privileged users can inject malicious scripts into group names, leading to stored XSS attacks against other users in Nextcloud Contacts.

- **Severity:** Medium 4.8 (`CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** No
- **Published:** 5 Jul 2018
- **Updated:** 5 Aug 2024
- **Also known as:** GHSA-hcc2-pgmx-p7rw

## What is CVE-2018-3764?

CVE-2018-3764 is a medium-severity cross-site scripting vulnerability in Nextcloud Contacts application, published on 5 Jul 2018. An attacker needs administrator access to exploit it, and only if a user opens a file or follows a link.

### Official description

In Nextcloud Contacts before 2.1.2, a missing sanitization of search results for an autocomplete field could lead to a stored XSS requiring user-interaction. The missing sanitization only affected group names, hence malicious search results could only be crafted by privileged users like admins or group admins.

Weakness: CWE-79 (Improper Neutralization of Input During Web Page Generation)

## Which versions are affected by CVE-2018-3764?

It affects 1 product.


Products: Nextcloud Contacts.

## How do I fix CVE-2018-3764?

No fix has been published for CVE-2018-3764 yet. Limit exposure of the affected software until one is available.

## Is CVE-2018-3764 being exploited?

There is no known exploitation of CVE-2018-3764 in the wild and no public exploit code.

## Other vulnerabilities in Nextcloud Contacts application

- [CVE-2021-39221](https://insights.sbomify.com/CVE-2021-39221/): XSS in Contacts (medium 6.4)
- [CVE-2020-8280](https://insights.sbomify.com/CVE-2020-8280/): Cross-site scripting in Nextcloud Contacts (medium 5.4)
- [CVE-2020-8281](https://insights.sbomify.com/CVE-2020-8281/): Cross-site scripting in Nextcloud Contacts (medium 5.4)
- [CVE-2020-8181](https://insights.sbomify.com/CVE-2020-8181/): File upload in Nextcloud Contact (medium 4.3)
- [CVE-2025-66554](https://insights.sbomify.com/CVE-2025-66554/): Nextcloud Contacts vulnerable to Stored XSS in contacts app via organisation and title field (low 3.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2018-3764 and fix it if it is affected.

What it is: CVE-2018-3764 is a medium-severity cross-site scripting vulnerability in Nextcloud Contacts application, published on 5 Jul 2018. An attacker needs administrator access to exploit it, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2018-3764 in the wild and no public exploit code.

Affected product: Nextcloud Contacts application. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2018-3764/ (Markdown: https://insights.sbomify.com/CVE-2018-3764/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2018-3764
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2018-3764
- OSV: https://osv.dev/vulnerability/CVE-2018-3764

---
From sbomify Insights: https://insights.sbomify.com/CVE-2018-3764/
Summaries are generated and may contain mistakes; the official description above is the record.