# CVE-2019-20437: Cross-site scripting in n/a

> Authenticated attackers can execute arbitrary scripts via stored XSS in custom claim dialects within WSO2 Identity Server configurations.

- **Severity:** Medium 6.1 (`CVSS:3.0/AC:L/AV:N/A:N/C:L/I:L/PR:N/S:C/UI:R`)
- **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:** 27 Jan 2020
- **Updated:** 5 Aug 2024
- **Also known as:** GHSA-pf48-fgcx-8ph4

## What is CVE-2019-20437?

CVE-2019-20437 is a medium-severity cross-site scripting vulnerability in Wso2 Api Manager, published on 27 Jan 2020. 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

An issue was discovered in WSO2 API Manager 2.6.0, WSO2 IS as Key Manager 5.7.0, and WSO2 Identity Server 5.8.0. When a custom claim dialect with an XSS payload is configured in the identity provider basic claim configuration, that payload gets executed, if a user picks up that dialect's URI as the provisioning claim in the advanced claim configuration of the same Identity Provider. The attacker also needs to have privileges to log in to the management console, and to add and update identity provider configurations.

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

## Which versions are affected by CVE-2019-20437?

It affects 2 products.


Products: Wso2 Api Manager, Wso2 Identity Server.

## How do I fix CVE-2019-20437?

No fix has been published for CVE-2019-20437 yet. Limit exposure of the affected software until one is available.

## Is CVE-2019-20437 being exploited?

There is no known exploitation of CVE-2019-20437 in the wild and no public exploit code.

## Other vulnerabilities in Wso2 Api Manager

- [CVE-2022-29464](https://insights.sbomify.com/CVE-2022-29464/): WSO2 Multiple Products Unrestrictive Upload of File (critical 9.8, exploited in the wild)
- [CVE-2024-6914](https://insights.sbomify.com/CVE-2024-6914/): Incorrect Authorization in Multiple WSO2 Products via Account Recovery SOAP Admin Service Leading to Account Takeover (critical 9.8)
- [CVE-2020-13226](https://insights.sbomify.com/CVE-2020-13226/): WSO2 API Manager vulnerable to SSRF (critical 9.8)
- [CVE-2025-2905](https://insights.sbomify.com/CVE-2025-2905/): An XML External Entity (XXE) vulnerability in Multiple WSO2 Products (critical 9.1)
- [CVE-2021-42646](https://insights.sbomify.com/CVE-2021-42646/): XML external entity in n/a (critical 9.1)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2019-20437 and fix it if it is affected.

What it is: CVE-2019-20437 is a medium-severity cross-site scripting vulnerability in Wso2 Api Manager, published on 27 Jan 2020. 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-2019-20437 in the wild and no public exploit code.

Affected product: Wso2 Api Manager. 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-2019-20437/ (Markdown: https://insights.sbomify.com/CVE-2019-20437/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2019-20437
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2019-20437
- OSV: https://osv.dev/vulnerability/CVE-2019-20437

---
From sbomify Insights: https://insights.sbomify.com/CVE-2019-20437/
Summaries are generated and may contain mistakes; the official description above is the record.