# CVE-2021-24275: Popup by Supsystic < 1.10.5 - Reflected Cross-Site scripting (XSS)

> Attackers can inject malicious scripts via the tab parameter in the Popup by Supsystic plugin options page, potentially compromising user sessions.

- **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:** 5 May 2021
- **Updated:** 3 Aug 2024
- **Also known as:** GHSA-xh33-9j66-fv2x

## What is CVE-2021-24275?

CVE-2021-24275 is a medium-severity cross-site scripting vulnerability in Popup by Supsystic, published on 5 May 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

The Popup by Supsystic WordPress plugin before 1.10.5 did not sanitise the tab parameter of its options page before outputting it in an attribute, leading to a reflected Cross-Site Scripting issue

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

## Which versions are affected by CVE-2021-24275?

It affects 1 product.


Products: Supsystic Popup.

## How do I fix CVE-2021-24275?

No fix has been published for CVE-2021-24275 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-24275 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2021-24275 exists.

Public exploit code:

- WordPress Plugin Popup 1.10.4 - Reflected Cross-Site Scripting (XSS) (exploitdb)
- Popup by Supsystic <1.10.5 - Cross-Site scripting (nuclei): http/cves/2021/CVE-2021-24275.yaml

## Other vulnerabilities in Popup by Supsystic

- [CVE-2023-3186](https://insights.sbomify.com/CVE-2023-3186/): Supsystic Popup < 1.10.19 - Prototype Pollution (critical 9.8)
- [CVE-2024-52434](https://insights.sbomify.com/CVE-2024-52434/): WordPress Popup by Supsystic plugin <= 1.10.29 - Remote Code Execution (RCE) vulnerability (critical 9.1)
- [CVE-2016-10915](https://insights.sbomify.com/CVE-2016-10915/): Cross-site request forgery in n/a (high 8.8)
- [CVE-2023-39997](https://insights.sbomify.com/CVE-2023-39997/): WordPress Popup by Supsystic plugin <= 1.10.19 - Broken Access Control Vulnerability (medium 5.3)
- [CVE-2023-51353](https://insights.sbomify.com/CVE-2023-51353/): WordPress Popup by Supsystic plugin <= 1.10.19 - Broken Access Control vulnerability (medium 5.3)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-24275 and fix it if it is affected.

What it is: CVE-2021-24275 is a medium-severity cross-site scripting vulnerability in Popup by Supsystic, published on 5 May 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: It is not confirmed as exploited in the wild, but public exploit code for CVE-2021-24275 exists.

Affected product: Popup by Supsystic. 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-2021-24275/ (Markdown: https://insights.sbomify.com/CVE-2021-24275/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-24275
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-24275
- OSV: https://osv.dev/vulnerability/CVE-2021-24275

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-24275/
Summaries are generated and may contain mistakes; the official description above is the record.