# CVE-2021-21278: Risk of code injection in RSSHub

> Attackers can execute arbitrary code on the server by injecting malicious scripts into RSSHub routes that use eval or Function constructors.

- **Severity:** High 8.6 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/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:** 26 Jan 2021
- **Updated:** 3 Aug 2024
- **Also known as:** GHSA-pgjj-866w-fc5c

## What is CVE-2021-21278?

CVE-2021-21278 is a high-severity code injection vulnerability in DIYgod RSSHub, published on 26 Jan 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

RSSHub is an open source, easy to use, and extensible RSS feed generator. In RSSHub before version 7f1c430 (non-semantic versioning) there is a risk of code injection. Some routes use `eval` or `Function constructor`, which may be injected by the target site with unsafe code, causing server-side security issues The fix in version 7f1c430 is to temporarily remove the problematic route and added a `no-new-func` rule to eslint.

Weakness: CWE-74 (Improper Neutralization of Special Elements in Output Used by a Downstream Component)

## Which versions are affected by CVE-2021-21278?

2 open source packages ship an affected version, including rsshub. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `rsshub` | npm | All versions to 1.0.0 | None |
| `rsshub` | npm | All versions to 1.0.0 | None |

Products: Rsshub Rsshub.

## How do I fix CVE-2021-21278?

No fix has been published for CVE-2021-21278 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-21278 being exploited?

There is no known exploitation of CVE-2021-21278 in the wild and no public exploit code.

## Other vulnerabilities in DIYgod RSSHub

- [CVE-2023-22493](https://insights.sbomify.com/CVE-2023-22493/): RSSHub is vulnerable to SSRF (Server-Side Request Forgery) (high 8.8)
- [CVE-2024-27927](https://insights.sbomify.com/CVE-2024-27927/): RSSHub vulnerable to SSRF in /mastodon, /zjoi, and /m4 (medium 6.5)
- [CVE-2024-27926](https://insights.sbomify.com/CVE-2024-27926/): RSSHub Cross-site Scripting vulnerability caused by internal media proxy (medium 6.1)
- [CVE-2023-26491](https://insights.sbomify.com/CVE-2023-26491/): RSSHub is vulnerable to cross-site scripting (XSS) via unvalidated URL parameters (medium 5.4)
- [CVE-2022-31110](https://insights.sbomify.com/CVE-2022-31110/): Denial of Service (DoS) vulnerability in RSSHub (medium 5.3)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-21278 and fix it if it is affected.

What it is: CVE-2021-21278 is a high-severity code injection vulnerability in DIYgod RSSHub, published on 26 Jan 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-2021-21278 in the wild and no public exploit code.

Affected packages and fixed versions:
- rsshub (npm): affected all versions up to 1.0.0; no fix listed
- rsshub (npm): affected all versions up to 1.0.0; 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-2021-21278/ (Markdown: https://insights.sbomify.com/CVE-2021-21278/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-21278
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-21278
- OSV: https://osv.dev/vulnerability/CVE-2021-21278

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-21278/
Summaries are generated and may contain mistakes; the official description above is the record.