---
id: CVE-2020-29238
title: >-
  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.
summary: >-
  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.
severity: high
cvss: 7.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N'
cwe:
  - CWE-190
vendor: expressvpn
product: expressvpn
affected:
  - expressvpn = 1.0
published: '2021-03-10'
updated: '2026-07-05'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2020-29238'
references:
  - url: 'http://ja1sharma.com/blog/2021/CVE-2020-29238/'
    label: cve@mitre.org
  - url: >-
      http://packetstormsecurity.com/files/162152/ExpressVPN-VPN-Router-1.0-Integer-Overflow.html
    label: cve@mitre.org
  - url: >-
      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
    label: cve@mitre.org
  - url: 'http://expressvpn.com'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'http://ja1sharma.com/blog/2021/CVE-2020-29238/'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: >-
      http://packetstormsecurity.com/files/162152/ExpressVPN-VPN-Router-1.0-Integer-Overflow.html
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: >-
      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
    label: af854a3a-2127-422b-91ae-364da2661108
tags:
  - nvd
  - exploit-available
epss: 0.16483
epssPercentile: 0.96878
exploitAvailable: true
ingestedAt: '2026-07-05T00:59:25.835Z'
exploits:
  exploitdb: true
  checkedAt: '2026-09-25T08:20:37.796Z'
---

## Overview

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.

## Affected

- `expressvpn = 1.0`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.