# CVE-2025-13736: Username Enumeration via Login Interface in Multiple WSO2 Products Allows User Account Discovery

> Attackers can enumerate valid usernames via the login interface when Multi-Attribute Login is enabled, facilitating targeted attacks.

- **Severity:** Low 3.7 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 6 Aug 2026
- **Updated:** 6 Aug 2026
- **Also known as:** GHSA-g8w9-p6wx-8fxc

## What is CVE-2025-13736?

CVE-2025-13736 is a low-severity vulnerability in Wso2 Api Manager, published on 6 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

When Multi-Attribute Login is enabled, the login interface fails to consistently mask the existence of user accounts. For valid users, the server resolves and displays their canonical username, while for non-existent users, it echoes the original input. This occurs regardless of the validate_username configuration.

The discovery of valid usernames can increase the risk of brute force attacks, social engineering attacks, and targeted information leakage. Attackers can leverage this information to craft more effective phishing campaigns or social engineering tactics to compromise user accounts or extract sensitive data.

Weakness: CWE-203 (Observable Discrepancy)

## Which versions are affected by CVE-2025-13736?

It affects 5 products.


Products: Wso2 Api Manager, Wso2 Identity Server, Wso2 Identity Server as Key Manager, Wso2 Open Banking Am, Wso2 Open Banking Iam.

## How do I fix CVE-2025-13736?

No fix has been published for CVE-2025-13736 yet. Limit exposure of the affected software until one is available.

## Is CVE-2025-13736 being exploited?

There is no known exploitation of CVE-2025-13736 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-2025-13736 and fix it if it is affected.

What it is: CVE-2025-13736 is a low-severity vulnerability in Wso2 Api Manager, published on 6 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2025-13736 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-2025-13736/ (Markdown: https://insights.sbomify.com/CVE-2025-13736/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-13736
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-13736
- OSV: https://osv.dev/vulnerability/CVE-2025-13736

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-13736/
Summaries are generated and may contain mistakes; the official description above is the record.