CVE-2026-109445

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

Assigner: VulnCheck
Reserved: 12.10.2026 Published: 13.11.2026 Updated: 13.11.2026

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.

Metrics

CVSS Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
CVSS Score: 9.3

Exploitability Metrics		Vulnerable System Impact Metrics		Subsequent System Impact Metrics
Attack Vector	Network	Confidentiality	High	Confidentiality	None
Attack Complexity	Low	Integrity	High	Integrity	None
Attack Requirements	None	Availability	High	Availability	None
Privileges Required	None
User Interaction	None

CVSS 4.0

CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CVSS Score: 9.8

Attack Vector	Network	Scope	Unchanged
Attack Complexity	Low	Confidentiality Impact	High
Privileges Required	None	Integrity Impact	High
User Interaction	None	Availability Impact	High

CVSS 3.1

Product Status

Vendor	PLANET Technology Corp.
Product	PLANET GS-5220-8P2T2S
Versions	Default: unaffected affected from 0 to 3.2412b261008 (excl.)

Vendor

PLANET Technology Corp.

Product

PLANET GS-5220-8P2T2S

Versions

Default: unaffected

affected from 0 to 3.2412b261008 (excl.)

Credits

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

References

Problem Types