# CVE-2021-21288: Server-side request forgery in CarrierWave

> Attackers can exploit the download feature to access internal network resources and gather infrastructure information via Server-Side Request Forgery.

- **Severity:** Medium 4.3 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 8 Feb 2021
- **Updated:** 3 Aug 2024
- **Also known as:** DEBIAN-CVE-2021-21288, GHSA-fwcm-636p-68r5

## What is CVE-2021-21288?

CVE-2021-21288 is a medium-severity server-side request forgery vulnerability in carrierwaveuploader carrierwave, published on 8 Feb 2021. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

CarrierWave is an open-source RubyGem which provides a simple and flexible way to upload files from Ruby applications. In CarrierWave before versions 1.3.2 and 2.1.1 the download feature has an SSRF vulnerability, allowing attacks to provide DNS entries or IP addresses that are intended for internal use and gather information about the Intranet infrastructure of the platform. This is fixed in versions 1.3.2 and 2.1.1.

Weakness: CWE-918 (Server-Side Request Forgery)

## Which versions are affected by CVE-2021-21288?

4 open source packages ship an affected version, including carrierwave. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `carrierwave` | RubyGems | All versions | 1.3.2 |
| `carrierwave` | RubyGems | All versions | 1.3.2 |
| `carrierwave` | RubyGems | From 2.0.0 | 2.1.1 |
| `carrierwave` | RubyGems | From 2.0.0 | 2.1.1 |

Products: Carrierwave Project Carrierwave.

## How do I fix CVE-2021-21288?

Upgrade carrierwave to a fixed version for your release line: 1.3.2 or 2.1.1.

## Is CVE-2021-21288 being exploited?

There is no known exploitation of CVE-2021-21288 in the wild and no public exploit code.

## Other vulnerabilities in carrierwaveuploader carrierwave

- [CVE-2021-21305](https://insights.sbomify.com/CVE-2021-21305/): Code Injection vulnerability in CarrierWave (high 7.4)
- [CVE-2024-29034](https://insights.sbomify.com/CVE-2024-29034/): CarrierWave's Content-Type allowlist bypass vulnerability which possibly leads to XSS remained (medium 6.8)
- [CVE-2023-49090](https://insights.sbomify.com/CVE-2023-49090/): CarrierWave has a content-type allowlist bypass vulnerability, possibly leading to XSS (medium 6.8)
- [CVE-2026-44587](https://insights.sbomify.com/CVE-2026-44587/): CarrierWave has a denylisted_content_type bypass via Unescaped Regex Metacharacters (medium 4.7)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-21288 and fix it if it is affected.

What it is: CVE-2021-21288 is a medium-severity server-side request forgery vulnerability in carrierwaveuploader carrierwave, published on 8 Feb 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-2021-21288 in the wild and no public exploit code.

Affected packages and fixed versions:
- carrierwave (RubyGems): affected all versions; fixed in 1.3.2
- carrierwave (RubyGems): affected all versions; fixed in 1.3.2
- carrierwave (RubyGems): affected from 2.0.0; fixed in 2.1.1
- carrierwave (RubyGems): affected from 2.0.0; fixed in 2.1.1

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-2021-21288/ (Markdown: https://insights.sbomify.com/CVE-2021-21288/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-21288
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-21288
- OSV: https://osv.dev/vulnerability/CVE-2021-21288

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-21288/
Summaries are generated and may contain mistakes; the official description above is the record.