CVE-2021-33558

PoC —

CVSS 3.1

7.5 high

EPSS

12%p96

Published

May 27, 2021 (May 27, 2021)

Modified

Jun 17, 2026

Description

Boa 0.94.13 allows remote attackers to obtain sensitive information via a misconfiguration involving backup.html, preview.html, js/log.js, log.html, email.html, online-users.html, and config.js. NOTE: multiple third parties report that this is a site-specific issue because those files are not part of Boa.

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

NVD CVE.org GitHub PoCs EPSS (12.3%)

In the news3 stories

Microsoft attributes alleged Chinese attack on Indian power grid to ‘Boa’ IoT vulnerability

The RecordJan 9, 00:00 UTC · Jan 9, 2023Vulnerability CVE-2021-35395 CVE-2022-27255 CVE-2017-9833+1 CVEs

Threat actors exploit discontinues Boa web servers to target critical infrastructure

Security AffairsNov 24, 08:47 UTC · Nov 24, 2022Threat actor CVE-2017-9833 CVE-2021-33558

Hackers Exploiting Abandoned Boa Web Servers to Target Critical Industries

The Hacker NewsNov 24, 05:54 UTC · Nov 24, 2022Vulnerability CVE-2017-9833 CVE-2021-33558