An integer buffer overflow in the Nginx webserver of ExpressVPN Router version 1 allows remote attackers to obtain sensitive information when the server running as reverse proxy via specially crafted request.
The product performs a calculation that can produce an integer overflow or wraparound when the logic assumes that the resulting value will always be larger than the original value. This occurs when an integer value is incremented to a value that is too large to store in the associated representation. When this occurs, the value may become a very small or negative number.
| Link | Tags |
|---|---|
| http://expressvpn.com | vendor advisory |
| https://bugcrowd.com/disclosures/4e8d5325-8e49-4ea3-962a-a088bbb73a3f/expressvpn-router-integer-buffer-overflow-server-info-disclosure-when-router-s-nginx-server-used-as-reverse-proxy-server | third party advisory |
| http://ja1sharma.com/blog/2021/CVE-2020-29238/ | third party advisory |
| http://packetstormsecurity.com/files/162152/ExpressVPN-VPN-Router-1.0-Integer-Overflow.html | vdb entry third party advisory |