# CVE-2021-20440: Business logic in API Connect

> An attacker with a stolen invitation link can register as a member of an API provider organization, gaining unauthorized access to internal resources.

- **Severity:** Medium 6.4 (`CVSS:3.0/AV:N/PR:L/A:L/C:H/AC:H/S:U/I:L/UI:N/RC:C/RL:O/E:U`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 15 Mar 2021
- **Updated:** 16 Sep 2024
- **Also known as:** GHSA-6f4h-wv9p-43cg

## What is CVE-2021-20440?

CVE-2021-20440 is a medium-severity vulnerability in Ibm Api Connect, published on 15 Mar 2021. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

IBM API Connect 10.0.0.0, and 2018.4.1.0 through 2018.4.1.13 does not restrict member registration to the intended recepient. An attacker who is a valid user in the user registry used by API Manager can use a stolen invitation link and register themselves as a member of an API provider organization. IBM X-Force ID: 196536.

## Which versions are affected by CVE-2021-20440?

It affects 1 product.


Products: Ibm Api Connect.

## How do I fix CVE-2021-20440?

No fix has been published for CVE-2021-20440 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-20440 being exploited?

There is no known exploitation of CVE-2021-20440 in the wild and no public exploit code.

## Other vulnerabilities in Ibm Api Connect

- [CVE-2019-4202](https://insights.sbomify.com/CVE-2019-4202/): Command injection in API Connect (critical 10.0)
- [CVE-2025-13915](https://insights.sbomify.com/CVE-2025-13915/): Authentication bypass in IBM API Connect (critical 9.8)
- [CVE-2018-1469](https://insights.sbomify.com/CVE-2018-1469/): Command injection in API Connect (critical 9.8)
- [CVE-2026-9074](https://insights.sbomify.com/CVE-2026-9074/): IBM API Connect SQL Injection (critical 9.1)
- [CVE-2019-4008](https://insights.sbomify.com/CVE-2019-4008/): Information disclosure in API Connect (critical 9.0)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-20440 and fix it if it is affected.

What it is: CVE-2021-20440 is a medium-severity vulnerability in Ibm Api Connect, published on 15 Mar 2021. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2021-20440 in the wild and no public exploit code.

Affected product: Ibm Api Connect. 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-2021-20440/ (Markdown: https://insights.sbomify.com/CVE-2021-20440/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-20440
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-20440
- OSV: https://osv.dev/vulnerability/CVE-2021-20440

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-20440/
Summaries are generated and may contain mistakes; the official description above is the record.