# CVE-2020-36939: Cassandra Web 0.5.0 - Remote File Read

> Unauthenticated attackers can read arbitrary system files and database credentials via path traversal in Cassandra Web.

- **Severity:** High 8.7 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 27 Jan 2026
- **Updated:** 8 Oct 2026
- **Also known as:** GHSA-8mfv-xhp5-48q9

## What is CVE-2020-36939?

CVE-2020-36939 is a high-severity path traversal vulnerability in avalanche123 Cassandra Web, published on 27 Jan 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Cassandra Web 0.5.0 contains a directory traversal vulnerability that allows unauthenticated attackers to read arbitrary files by manipulating path traversal parameters. Attackers can exploit the disabled Rack::Protection module to read sensitive system files like /etc/passwd and retrieve Apache Cassandra database credentials.

Weakness: CWE-22 (Improper Limitation of a Pathname to a Restricted Directory)

## Which versions are affected by CVE-2020-36939?

2 open source packages ship an affected version, including cassandra-web.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `cassandra-web` | RubyGems | All versions to 0.5.0 | None |
| `cassandra-web` | RubyGems | All versions to 0.5.0 | None |

## How do I fix CVE-2020-36939?

No fix has been published for CVE-2020-36939 yet. Limit exposure of the affected software until one is available.

## Is CVE-2020-36939 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2020-36939 exists.

Public exploit code:

- Cassandra Web File Read Vulnerability (metasploit)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2020-36939 and fix it if it is affected.

What it is: CVE-2020-36939 is a high-severity path traversal vulnerability in avalanche123 Cassandra Web, published on 27 Jan 2026. 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-2020-36939 exists.

Affected packages and fixed versions:
- cassandra-web (RubyGems): affected all versions up to 0.5.0; no fix listed
- cassandra-web (RubyGems): affected all versions up to 0.5.0; 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-2020-36939/ (Markdown: https://insights.sbomify.com/CVE-2020-36939/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-36939
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-36939
- OSV: https://osv.dev/vulnerability/CVE-2020-36939

---
From sbomify Insights: https://insights.sbomify.com/CVE-2020-36939/
Summaries are generated and may contain mistakes; the official description above is the record.