# CVE-2021-32641: Reflected XSS when using flashMessages

> Attackers can execute arbitrary code via reflected XSS in Auth0 Lock when flashMessage or languageDictionary features process user input.

- **Severity:** High 8.1 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 4 Jun 2021
- **Updated:** 3 Aug 2024
- **Also known as:** GHSA-jr3j-whm4-9wwm

## What is CVE-2021-32641?

CVE-2021-32641 is a high-severity cross-site scripting vulnerability in auth0 lock, published on 4 Jun 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

auth0-lock is Auth0's signin solution. Versions of nauth0-lock before and including `11.30.0` are vulnerable to reflected XSS. An attacker can execute arbitrary code when the library's `flashMessage` feature is utilized and user input or data from URL parameters is incorporated into the `flashMessage` or the library's `languageDictionary` feature is utilized and user input or data from URL parameters is incorporated into the `languageDictionary`. The vulnerability is patched in version 11.30.1.

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

## Which versions are affected by CVE-2021-32641?

2 open source packages ship an affected version, including auth0-lock. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `auth0-lock` | npm | All versions | 11.30.1 |
| `auth0-lock` | npm | All versions | 11.30.1 |

Products: Auth0 Lock.

## How do I fix CVE-2021-32641?

Upgrade auth0-lock to 11.30.1 or later.

## Is CVE-2021-32641 being exploited?

There is no known exploitation of CVE-2021-32641 in the wild and no public exploit code.

## Other vulnerabilities in auth0 lock

- [CVE-2020-15119](https://insights.sbomify.com/CVE-2020-15119/): DOM-based XSS in auth0-lock (medium 6.4)
- [CVE-2022-29172](https://insights.sbomify.com/CVE-2022-29172/): HTML injection with additional signup fields (medium 6.1)
- [CVE-2019-20174](https://insights.sbomify.com/CVE-2019-20174/): auth0-lock vulnerable to XSS via unsanitized placeholder property (medium 6.1)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-32641 and fix it if it is affected.

What it is: CVE-2021-32641 is a high-severity cross-site scripting vulnerability in auth0 lock, published on 4 Jun 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2021-32641 in the wild and no public exploit code.

Affected packages and fixed versions:
- auth0-lock (npm): affected all versions; fixed in 11.30.1
- auth0-lock (npm): affected all versions; fixed in 11.30.1

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-2021-32641/ (Markdown: https://insights.sbomify.com/CVE-2021-32641/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-32641
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-32641
- OSV: https://osv.dev/vulnerability/CVE-2021-32641

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-32641/
Summaries are generated and may contain mistakes; the official description above is the record.