# CVE-2021-36686: Cross-site Scripting in yapi-vendor

> Attackers can execute arbitrary code via XSS in the YAPI interface API edit page, compromising user sessions and data.

- **Severity:** Medium 5.4 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/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:** 26 Jan 2023
- **Updated:** 1 Apr 2025
- **Also known as:** CVE-2021-33237, GHSA-4jqw-vfmj-9rmh

## What is CVE-2021-36686?

CVE-2021-36686 is a medium-severity cross-site scripting vulnerability in n/a, published on 26 Jan 2023. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.

### Official description

Cross Site Scripting (XSS) vulnerability in yapi 1.9.1 allows attackers to execute arbitrary code via the /interface/api edit page.

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

## Which versions are affected by CVE-2021-36686?

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


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `yapi-vendor` | npm | All versions to 1.9.1 | None |
| `yapi-vendor` | npm | All versions to 1.9.1 | None |

Products: Ymfe Yapi.

## How do I fix CVE-2021-36686?

No fix has been published for CVE-2021-36686 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-36686 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2021-36686 exists.

## Other vulnerabilities in n/a

- [CVE-2025-70059](https://insights.sbomify.com/CVE-2025-70059/): Denial of service in n/a (high 7.5)
- [CVE-2025-70058](https://insights.sbomify.com/CVE-2025-70058/): yapi disables TLS/SSL certificate validation via rejectUnauthorized: false in Axios HTTPS agent (high 7.4)
- [CVE-2025-70060](https://insights.sbomify.com/CVE-2025-70060/): Cross-site scripting in n/a (medium 5.4)
- [CVE-2018-17574](https://insights.sbomify.com/CVE-2018-17574/): Cross-site Scripting in yapi-vendor (medium 5.4)
- [CVE-2021-27884](https://insights.sbomify.com/CVE-2021-27884/): Weak JSON Web Token in yapi-vendor (medium 5.1)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-36686 and fix it if it is affected.

What it is: CVE-2021-36686 is a medium-severity cross-site scripting vulnerability in n/a, published on 26 Jan 2023. Any signed-in user can exploit it over the network, 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-2021-36686 exists.

Affected packages and fixed versions:
- yapi-vendor (npm): affected all versions up to 1.9.1; no fix listed
- yapi-vendor (npm): affected all versions up to 1.9.1; no fix listed

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-2021-36686/ (Markdown: https://insights.sbomify.com/CVE-2021-36686/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-36686
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-36686
- OSV: https://osv.dev/vulnerability/CVE-2021-36686

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-36686/
Summaries are generated and may contain mistakes; the official description above is the record.