Executive brief
DrayTek VigorSwitch is a managed network switch used in corporate environments to route and manage data traffic. A buffer overflow in the mail alert functionality allows authenticated administrators to trigger a denial of service or potentially execute arbitrary code on the device by sending specially crafted email configuration input. While this requires valid admin credentials, successful exploitation could give attackers complete control over network infrastructure.
Technical details
The vulnerability is a classic buffer overflow (CWE-120) in the mail_mailalert function of multiple VigorSwitch firmware versions. The flaw occurs when the device concatenates multiple SMTP receiver email addresses into a fixed-size buffer without validating the remaining buffer capacity. An authenticated remote attacker with administrative credentials can exploit this via the web management interface by providing oversized email address input, leading to stack corruption. This can result in denial of service or, with careful payload crafting, arbitrary code execution on the affected appliance. Patches have been released for all affected models as of August 2026.
Affected products
- DrayTek VigorSwitch G2540xs before 3.9.10
- DrayTek VigorSwitch P2540xs before 3.9.10
- DrayTek VigorSwitch FX2120 before 3.9.10
- DrayTek VigorSwitch G2282x before 2.10.6
- DrayTek VigorSwitch P2282x before 2.10.6
- DrayTek VigorSwitch Q2300x before 2.10.7
- DrayTek VigorSwitch PQ2300xb before 2.10.7
- DrayTek VigorSwitch G2542x before 3.10.6
- DrayTek VigorSwitch P2542x before 3.10.6
- DrayTek VigorSwitch P2542xh before 3.10.6
- DrayTek VigorSwitch PX2060 before 2.9.10
- DrayTek VigorSwitch G1280 before 2.9.10
- DrayTek VigorSwitch P1280 before 2.9.10
- DrayTek VigorSwitch P1281x before 2.9.10
- DrayTek VigorSwitch G1282 before 2.9.10
- DrayTek VigorSwitch P1282 before 2.9.10
- DrayTek VigorSwitch G2121 before 2.9.10
- DrayTek VigorSwitch P2121 before 2.9.10
- DrayTek VigorSwitch PQ2121x before 2.9.10
- DrayTek VigorSwitch Q2121x before 2.9.10
- DrayTek VigorSwitch G2280x before 2.9.10
- DrayTek VigorSwitch P2280x before 2.9.10
- DrayTek VigorSwitch Q2200x before 2.9.10
- DrayTek VigorSwitch PQ2200xb before 2.9.10
- DrayTek VigorSwitch G2100 before 2.9.10
- DrayTek VigorSwitch P2100 before 2.9.10
- DrayTek VigorSwitch G2540x before 2.9.10
- DrayTek VigorSwitch P2540x before 2.9.10
Timeline
- 2026-08-24: disclosed
- 2026-08-24: patched: Fixed firmware versions released for all affected models