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Public proof of concept

CVE-2021-33558

A public proof of concept exists; no exploitation attested.

  • Published2021-05-27

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

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.

Timeline

dates in UTC
  1. 2021-05-2711:15CVE publishedNVD

Versions per branch

NVD
Boa
BranchAffectedFixed in
0.94= 0.94.13no fix published

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Fix

Advisories and patches

Detection

read 2026-11-01 01:02 UTC
Nuclei template
available
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof of concept
Metasploit modules
none listed
Metasploit Framework

Sources

Identifiers

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Published
2021-05-27
Last Modified
2026-06-17
NVD status
Modified

Frequently asked questions

What is CVE-2021-33558?

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.

Is CVE-2021-33558 actively exploited?

Active exploitation of CVE-2021-33558 has not been confirmed. Its EPSS score was 12.3% on 2026-11-05, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2021-33558?

CVE-2021-33558 has a CVSS v3 base score of 7.5 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N.

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Sources for this record