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Public proof of conceptFix available

CVE-2021-33393

A public proof of concept exists; no exploitation attested.

  • Published2021-06-09
  • Fixed in2.25

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

lfs/backup in IPFire 2.25-core155 does not ensure that /var/ipfire/backup/bin/backup.pl is owned by the root account. It might be owned by an unprivileged account, which could potentially be used to install a Trojan horse backup.pl script that is later executed by root. Similar problems with the ownership/permissions of other files may be present as well.

Timeline

dates in UTC
  1. 2021-05-17Exploit-DB entryExploit-DB
  2. 2021-06-0922:15CVE publishedNVD

Observed activity

isMalicious corpus · updated 2026-11-03 21:37 UTC
Indicators tagged with this CVE, per day0 indicators over 7 days
Block these indicators
  • Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2021-33393?format=txt
  • CSV export: https://api.ismalicious.com/edl/cve/CVE-2021-33393?format=csv
  • TAXII collection of exploited CVEs
  • The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD
Ipfire
BranchAffectedFixed in
2.25< 2.252.25
2.25= 2.25no fix published

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

Fix

  1. Update Ipfire to 2.25

Advisories and patches

Detection

read 2026-11-02 22:42 UTC
Nuclei template
none so far
ProjectDiscovery
Exploit-DB
EDB-49869
Exploit-DB
Proof-of-concept repositories
1 repository, unverifiedjoaoaugustom/IPFire_2.25_RCE_Authenticated
PoC-in-GitHub
Metasploit modules
1 moduleexploit/linux/http/ipfire_pakfire_execrank: excellentModule metadata: Metasploit Framework, © Rapid7, Inc., BSD-3-Clause.
Metasploit Framework

Sources

Identifiers

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Published
2021-06-09
Last Modified
2026-06-17
NVD status
Modified

Frequently asked questions

What is CVE-2021-33393?

lfs/backup in IPFire 2.25-core155 does not ensure that /var/ipfire/backup/bin/backup.pl is owned by the root account. It might be owned by an unprivileged account, which could potentially be used to install a Trojan horse backup.pl script that is later executed by root. Similar problems with the ownership/permissions of other files may be present as well.

Is CVE-2021-33393 actively exploited?

Active exploitation of CVE-2021-33393 has not been confirmed. Its EPSS score was 59.3% on 2026-11-03, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2021-33393?

CVE-2021-33393 has a CVSS v3 base score of 8.8 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.

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Sources for this record