# CVE-2021-40721: Adobe Connect Reflected Cross Site Scripting

> An attacker can execute malicious JavaScript in a victim's browser by tricking them into visiting a crafted URL in Adobe Connect.

- **Severity:** Medium 6.1 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** No
- **Published:** 15 Oct 2021
- **Updated:** 23 Apr 2025
- **Also known as:** GHSA-fwq9-fc5m-x5cc

## What is CVE-2021-40721?

CVE-2021-40721 is a medium-severity cross-site scripting vulnerability in Adobe Connect, published on 15 Oct 2021. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official description

Adobe Connect version 11.2.3 (and earlier) is affected by a reflected Cross-Site Scripting (XSS) vulnerability. If an attacker is able to convince a victim to visit a URL referencing a vulnerable page, malicious JavaScript content may be executed within the context of the victim's browser.

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

## Which versions are affected by CVE-2021-40721?

It affects 1 product.


Products: Adobe Connect.

## How do I fix CVE-2021-40721?

No fix has been published for CVE-2021-40721 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-40721 being exploited?

There is no known exploitation of CVE-2021-40721 in the wild and no public exploit code.

## Other vulnerabilities in Adobe Connect

- [CVE-2017-11291](https://insights.sbomify.com/CVE-2017-11291/): Server-side request forgery in Adobe Connect 9.6.2 and earlier versions (critical 10.0)
- [CVE-2026-75682](https://insights.sbomify.com/CVE-2026-75682/): Adobe Connect | Improper Neutralization of Special Elements used in an SQL Command ('SQL Injection') (CWE-89) (critical 9.9)
- [CVE-2023-4661](https://insights.sbomify.com/CVE-2023-4661/): SQLi in Saphira Connect (critical 9.8)
- [CVE-2023-4662](https://insights.sbomify.com/CVE-2023-4662/): RCE in Saphira Connect (critical 9.8)
- [CVE-2021-40719](https://insights.sbomify.com/CVE-2021-40719/): Adobe Connect Deserialization of Untrusted Data Remote Code Execution (critical 9.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-40721 and fix it if it is affected.

What it is: CVE-2021-40721 is a medium-severity cross-site scripting vulnerability in Adobe Connect, published on 15 Oct 2021. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2021-40721 in the wild and no public exploit code.

Affected product: Adobe Connect. 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-2021-40721/ (Markdown: https://insights.sbomify.com/CVE-2021-40721/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-40721
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-40721
- OSV: https://osv.dev/vulnerability/CVE-2021-40721

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-40721/
Summaries are generated and may contain mistakes; the official description above is the record.