# CVE-2021-36873: WordPress iQ Block Country plugin <= 1.2.11 - Authenticated Persistent Cross-Site Scripting (XSS) vulnerability

> Authenticated attackers can inject persistent scripts via the block message parameter in the iQ Block Country plugin, potentially compromising user sessions.

- **Severity:** Medium 5.5 (`CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:L/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 23 Sep 2021
- **Updated:** 28 Apr 2026
- **Also known as:** GHSA-5mcg-fw36-rwf2

## What is CVE-2021-36873?

CVE-2021-36873 is a medium-severity cross-site scripting vulnerability in Webence iQ Block Country, published on 23 Sep 2021. An attacker needs administrator access to exploit it, with no action from the victim.

### Official description

Authenticated Persistent Cross-Site Scripting (XSS) vulnerability in WordPress iQ Block Country plugin (versions <= 1.2.11). Vulnerable parameter: &blockcountry_blockmessage.

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

## Which versions are affected by CVE-2021-36873?

It affects 1 product.


Products: Webence Iq Block Country.

## How do I fix CVE-2021-36873?

No fix has been published for CVE-2021-36873 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-36873 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2021-36873 exists.

Public exploit code:

- WordPress iQ Block Country <=1.2.11 - Cross-Site Scripting (nuclei): http/cves/2021/CVE-2021-36873.yaml

## Other vulnerabilities in Webence iQ Block Country

- [CVE-2022-1762](https://insights.sbomify.com/CVE-2022-1762/): iQ Block Country < 1.2.20 - Protection Bypass due to IP Spoofing (high 7.5)
- [CVE-2022-41155](https://insights.sbomify.com/CVE-2022-41155/): WordPress iQ Block Country plugin <= 1.2.18 - Block BYPASS vulnerability (medium 5.3)
- [CVE-2022-0246](https://insights.sbomify.com/CVE-2022-0246/): iQ Block Country < 1.2.13 - Admin+ Arbitrary File Deletion via Zip Slip (medium 4.9)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-36873 and fix it if it is affected.

What it is: CVE-2021-36873 is a medium-severity cross-site scripting vulnerability in Webence iQ Block Country, published on 23 Sep 2021. An attacker needs administrator access to exploit it, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2021-36873 exists.

Affected product: Webence iQ Block Country. 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-2021-36873/ (Markdown: https://insights.sbomify.com/CVE-2021-36873/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-36873
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-36873
- OSV: https://osv.dev/vulnerability/CVE-2021-36873

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-36873/
Summaries are generated and may contain mistakes; the official description above is the record.