CVE-2026-109445

CRITICAL 9.8

PLANET GS-5220-8P2T2S Stack Buffer Overflow via webstax_auth Cookie

CVSS Score

9.8

EPSS Score

0.0%

EPSS Percentile

0th

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.

CWE	CWE-121
Vendor	planet technology corp.
Product	planet gs-5220-8p2t2s
Published	Nov 13, 2026

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CVSS v3 Breakdown

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Affected Versions

PLANET Technology Corp. / PLANET GS-5220-8P2T2S

0 < 3.2412b261008

References

NVD ↗ CVE.org ↗ EPSS Data ↗

planet.com.tw: https://www.planet.com.tw/en/support/security-advisory/12 vulncheck.com: https://www.vulncheck.com/advisories/planet-gs-5220-8p2t2s-stack-buffer-overflow-via-webstax-auth-cookie

Credits

Tianchang Yang and Syed Rafiul Hussain (SyNSec Lab, Penn State University)