# CVE-2023-28845: Chat room membership disclosed via autocompletion in Nextcloud talk

> Attackers can view member lists of private Nextcloud Talk conversations without being members, exposing user identities.

- **Severity:** Low 3.5 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:N/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** No
- **Published:** 31 Mar 2023
- **Updated:** 11 Feb 2025
- **Also known as:** GHSA-3m6r-479j-4chf

## What is CVE-2023-28845?

CVE-2023-28845 is a low-severity vulnerability in nextcloud security-advisories, published on 31 Mar 2023. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.

### Official description

Nextcloud talk is a video & audio conferencing app for Nextcloud. In affected versions the talk app does not properly filter access to a conversations member list. As a result an attacker could use this vulnerability to gain information about the members of a Talk conversation, even if they themselves are not members. It is recommended that the Nextcloud Talk is upgraded to 14.0.9 or 15.0.4. There are no known workarounds for this vulnerability.

Weakness: CWE-284 (Improper Access Control)

## Which versions are affected by CVE-2023-28845?

It affects 1 product.


Products: Nextcloud Talk.

## How do I fix CVE-2023-28845?

No fix has been published for CVE-2023-28845 yet. Limit exposure of the affected software until one is available.

## Is CVE-2023-28845 being exploited?

There is no known exploitation of CVE-2023-28845 in the wild and no public exploit code.

## Other vulnerabilities in nextcloud security-advisories

- [CVE-2020-8180](https://insights.sbomify.com/CVE-2020-8180/): Code injection in Nextcloud Talk (critical 9.9)
- [CVE-2021-32689](https://insights.sbomify.com/CVE-2021-32689/): Nextcloud Talk not properly disassociating users from chats after account deletion (high 8.1)
- [CVE-2023-39957](https://insights.sbomify.com/CVE-2023-39957/): Path traversal allows tricking the Talk Android app into writing files into it's root directory (high 7.2)
- [CVE-2021-32676](https://insights.sbomify.com/CVE-2021-32676/): Session Fixation in Nextcloud Talk (medium 6.5)
- [CVE-2021-39222](https://insights.sbomify.com/CVE-2021-39222/): XSS in Talk (medium 6.4)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2023-28845 and fix it if it is affected.

What it is: CVE-2023-28845 is a low-severity vulnerability in nextcloud security-advisories, published on 31 Mar 2023. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2023-28845 in the wild and no public exploit code.

Affected product: nextcloud security-advisories. 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-2023-28845/ (Markdown: https://insights.sbomify.com/CVE-2023-28845/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-28845
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-28845
- OSV: https://osv.dev/vulnerability/CVE-2023-28845

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-28845/
Summaries are generated and may contain mistakes; the official description above is the record.