# CVE-2020-18698: Lin-CMS-Flask vulnerable to Improper Authentication

> Remote attackers can perform unrestricted brute force login attempts on Lin-CMS-Flask, potentially leading to account takeover.

- **Severity:** Critical 9.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 16 Aug 2021
- **Updated:** 4 Aug 2024
- **Also known as:** GHSA-h6r2-pgvx-683c, PYSEC-2021-339

## What is CVE-2020-18698?

CVE-2020-18698 is a critical authentication bypass vulnerability in n/a, published on 16 Aug 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Improper Authentication in Lin-CMS-Flask v0.1.1 allows remote attackers to launch brute force login attempts without restriction via the 'login' function in the component 'app/api/cms/user.py'.

Weakness: CWE-307 (Improper Restriction of Excessive Authentication Attempts)

## Which versions are affected by CVE-2020-18698?

3 open source packages ship an affected version, including lin-cms and Lin-CMS. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `lin-cms` | PyPI | All versions | None |
| `lin-cms` | PyPI | All versions | None |
| `Lin-CMS` | PyPI | All versions | None |

Products: Talelin Lin-Cms-Flask.

## How do I fix CVE-2020-18698?

No fix has been published for CVE-2020-18698 yet. Limit exposure of the affected software until one is available.

## Is CVE-2020-18698 being exploited?

There is no known exploitation of CVE-2020-18698 in the wild and no public exploit code.

## Other vulnerabilities in n/a

- [CVE-2020-18701](https://insights.sbomify.com/CVE-2020-18701/): Auth bypass in n/a (critical 9.8)
- [CVE-2020-18699](https://insights.sbomify.com/CVE-2020-18699/): Lin-CMS-Flask Cross Site Scripting (XSS) vulnerability (medium 6.1)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2020-18698 and fix it if it is affected.

What it is: CVE-2020-18698 is a critical authentication bypass vulnerability in n/a, published on 16 Aug 2021. 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-2020-18698 in the wild and no public exploit code.

Affected packages and fixed versions:
- lin-cms (PyPI): affected all versions; no fix listed
- lin-cms (PyPI): affected all versions; no fix listed
- Lin-CMS (PyPI): affected all versions; 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-2020-18698/ (Markdown: https://insights.sbomify.com/CVE-2020-18698/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-18698
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-18698
- OSV: https://osv.dev/vulnerability/CVE-2020-18698

---
From sbomify Insights: https://insights.sbomify.com/CVE-2020-18698/
Summaries are generated and may contain mistakes; the official description above is the record.