# CVE-2022-23656: Cross-site scripting vulnerability in Zulip Server

> An attacker can execute arbitrary JavaScript in a victim's browser via a crafted full name on the recent topics page in Zulip Server.

- **Severity:** Medium 4.6 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:L/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:** 2 Mar 2022
- **Updated:** 23 Apr 2025
- **Also known as:** GHSA-fc77-h3jc-6mfv

## What is CVE-2022-23656?

CVE-2022-23656 is a medium-severity cross-site scripting vulnerability in zulip, published on 2 Mar 2022. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.

### Official description

Zulip is an open source team chat app. The `main` development branch of Zulip Server from June 2021 and later is vulnerable to a cross-site scripting vulnerability on the recent topics page. An attacker could maliciously craft a full name for their account and send messages to a topic with several participants; a victim who then opens an overflow tooltip including this full name on the recent topics page could trigger execution of JavaScript code controlled by the attacker. Users running a Zulip server from the main branch should upgrade from main (2022-03-01 or later) again to deploy this fix.

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

## Which versions are affected by CVE-2022-23656?

It affects 1 product.


Products: Zulip Zulip Server.

## How do I fix CVE-2022-23656?

No fix has been published for CVE-2022-23656 yet. Limit exposure of the affected software until one is available.

## Is CVE-2022-23656 being exploited?

There is no known exploitation of CVE-2022-23656 in the wild and no public exploit code.

## Other vulnerabilities in zulip

- [CVE-2019-18933](https://insights.sbomify.com/CVE-2019-18933/): Information disclosure in n/a (critical 9.8)
- [CVE-2020-15070](https://insights.sbomify.com/CVE-2020-15070/): Code injection in n/a (high 8.8)
- [CVE-2017-0910](https://insights.sbomify.com/CVE-2017-0910/): Missing authorization in Zulip Server (high 8.8)
- [CVE-2025-31478](https://insights.sbomify.com/CVE-2025-31478/): Zulip Authentication Backend Configuration Bypass (high 8.2)
- [CVE-2023-33186](https://insights.sbomify.com/CVE-2023-33186/): Cross-site scripting vulnerability in Zulip Server development branch via topic tooltip (high 8.2)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2022-23656 and fix it if it is affected.

What it is: CVE-2022-23656 is a medium-severity cross-site scripting vulnerability in zulip, published on 2 Mar 2022. 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-2022-23656 in the wild and no public exploit code.

Affected product: zulip. 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-2022-23656/ (Markdown: https://insights.sbomify.com/CVE-2022-23656/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2022-23656
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2022-23656
- OSV: https://osv.dev/vulnerability/CVE-2022-23656

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From sbomify Insights: https://insights.sbomify.com/CVE-2022-23656/
Summaries are generated and may contain mistakes; the official description above is the record.