# CVE-2020-36533: Klapp App JSON Web Token improper authentication

> Remote attackers can bypass authentication in Klapp App due to improper JSON Web Token handling, potentially gaining unauthorized access.

- **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:** 3 Jun 2022
- **Updated:** 15 Apr 2025
- **Also known as:** GHSA-77mh-9xg9-p4r9

## What is CVE-2020-36533?

CVE-2020-36533 is a low-severity authentication bypass vulnerability in Klapp App, published on 3 Jun 2022. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

A vulnerability was found in Klapp App and classified as problematic. This issue affects some unknown processing of the JSON Web Token Handler. The manipulation leads to weak authentication. The attack may be initiated remotely.

Weakness: CWE-287 (Improper Authentication)

## Which versions are affected by CVE-2020-36533?

It affects 1 product.


Products: Klapp App.

## How do I fix CVE-2020-36533?

No fix has been published for CVE-2020-36533 yet. Limit exposure of the affected software until one is available.

## Is CVE-2020-36533 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2020-36533 exists.

## Other vulnerabilities in Klapp App

- [CVE-2020-36532](https://insights.sbomify.com/CVE-2020-36532/): Klapp App Authorization Credentials information disclosure (medium 4.3)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2020-36533 and fix it if it is affected.

What it is: CVE-2020-36533 is a low-severity authentication bypass vulnerability in Klapp App, published on 3 Jun 2022. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2020-36533 exists.

Affected product: Klapp App. 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-2020-36533/ (Markdown: https://insights.sbomify.com/CVE-2020-36533/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-36533
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-36533
- OSV: https://osv.dev/vulnerability/CVE-2020-36533

---
From sbomify Insights: https://insights.sbomify.com/CVE-2020-36533/
Summaries are generated and may contain mistakes; the official description above is the record.