---
id: "CVE-2026-109445"
page: "https://infrastack.ai/live/CVE-2026-109445"
kind: "vulnerability"
aliases: ["CVE-2026-109445"]
title: "PLANET GS-5220 switch: oversized cookie overflows stack, unauthenticated attackers"
severity: "critical"
cvss: 9.8
epss: null
exploited: false
status: "open"
category: "infrastructure"
products: []
ecosystems: []
tags: ["firmware", "gs-5220-8p2t2s", "infrastructure", "network-switch", "planet"]
not_affected_if: ["fixed-firmware", "management-isolated"]
published_at: "2026-11-13T15:17:30+00:00"
first_seen_at: "2026-11-13T15:46:15+00:00"
updated_at: "2026-11-13T15:48:07+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-109445", "first_seen_at": "2026-11-13T15:46:15+00:00"}]
exploit_sources: []
---

# PLANET GS-5220 switch: oversized cookie overflows stack, unauthenticated attackers

Link for people: https://infrastack.ai/live/CVE-2026-109445 (this .md is for agents)

PLANET GS-5220-8P2T2S switches (hardware version 3.0) with firmware before 3.2412b261008 have a stack buffer overflow in the webstax_auth cookie handling. An unauthenticated attacker can send an oversized cookie over HTTP to corrupt stack memory, causing crashes or potential code execution on the device.

_Summary, check and fix written by a model from the sources; labelled as such._

## How to check

- Check the firmware version in the switch's web management interface or system information page; compare it with `3.2412b261008`.
- Confirm the hardware version is `3.0` on the device label or system information.
- Check whether the web management interface is reachable from untrusted networks.

## Fix

- PLANET GS-5220-8P2T2S hardware version 3.0: firmware `3.2412b261008` or later.

## Timeline

- 2026-11-13T15:46:15+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-109445

## Documents

- [advisory] Third-party advisory: www.vulncheck.com https://www.vulncheck.com/advisories/planet-gs-5220-8p2t2s-stack-buffer-overflow-via-webstax-auth-cookie

## From the sources

PLANET GS-5220-8P2T2S (hardware version 3.0) firmware versions before 3.2412b261008 contains a stack-based buffer overflow vulnerability that allows unauthenticated attackers to corrupt stack memory by submitting an oversized webstax_auth HTTP Cookie value that is copied into a fixed-size stack buffer without length validation. Attackers can send a crafted unauthenticated HTTP request with an oversized cookie to overwrite the saved return address and corrupt stack memory, leading to memory corruption and potential denial of service on the device.

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_Free to read, with fair use of about 60 pages a minute. For higher limits or API access: sales@infrastack.ai_