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NVD / CVE Program· CNA mitre

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.

Noroxi assessment

Priority: Plan (action score 53/100)

  • A ready-made attack module is public (Metasploit); exploiting it takes no special expertise.
  • Public proof-of-concept code exists (Exploit-DB, GitHub); there is no record of exploitation in the wild.
  • Probability of exploitation in the next 30 days: 59.3% (FIRST EPSS); higher than 99.1% of all records.
  • Anyone who can reach it over the internet can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
  • No fixed version is recorded, but the references include a patch (commit or PR) link.

Add it to your regular patch cycle. See the fix and affected versions sections below.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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.

HighCVSS 8.8 · v3.1—Weaponized No fix recorded
Published
Jun 9, 2021
Updated
Jun 16, 2026
EPSS
59.3% · 99th percentile
CWE
—

Report tools

JSON

Action score

53

Plan

Add it to your regular patch cycle.

CVSS
35 / 40 · 8.8 / 10
CISA KEV
0 / 30 · Not listed
EPSS
18 / 30 · 59.3%

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • Weaponized exploit exists
  • No fixed version yet

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2021-33393

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
ipfireipfire

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • ipfire ipfirebefore 2.25
  • ipfire ipfire2.25

Same product

ipfire: all records

Other highest-scoring records for the same primary product.

  • CVE-2017-9757IPFire 2.19 has a Remote Command Injection vulnerability in ids.cgi via the OINKCODE parameter, which is mishandled by a shell.
    46Plan
  • CVE-2025-34311IPFire < v2.29 Command Injection via Proxy Report Creation
    38Monitor
  • CVE-2018-16232An authenticated command injection vulnerability exists in IPFire Firewall before 2.21 Core Update 124 in backup.cgi.
    37Monitor

Published before and after this one in the same product

  • Later →CVE-2020-19202Jun 17, 2021 · An authenticated Stored XSS (Cross-site Scripting) exists in the "captive.cgi" Captive Portal via the "Title of Login Page" text box or "TIT
    21Monitor
  • Later →CVE-2020-21142Jun 28, 2021 · Cross Site Scripting (XSS) vulnerabilty in IPFire 2.23 via the IPfire web UI in the mail.cgi.
    24Monitor
  • Later →CVE-2020-19204Jul 12, 2021 · An authenticated Stored Cross-Site Scriptiong (XSS) vulnerability exists in Lightning Wire Labs IPFire 2.21 (x86_64) - Core Update 130 in th
    21Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

No fix version is recorded for this entry. Check the references for vendor advisories.

Exploit status

Weaponized

A ready exploit tool or active in-the-wild use is known for this vulnerability. This should be your top priority.

Evidence

  • Metasploit module ×1
  • Exploit-DB entry ×1
  • Proof-of-concept repository on GitHub ×1

Noroxi does not host or link to exploit code. Metasploit module names and Nuclei template ids are shown (names, not code); Exploit-DB entries and PoC repositories are given as counts only.

Public exploit evidence
SourceKindDate
Exploit-DB entrywebapps2021-05-17
Metasploit moduleexploit/linux/http/ipfire_pakfire_execIPFire 2.25 Core Update 156 and Prior pakfire.cgi Authenticated RCEexploit2021-05-17
Proof-of-concept repository on GitHubstars:12026-05-16

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

  1. First PoC-24 d
  2. Metasploit-24 d
  3. Published
  4. TodayNov 10, 2026+1980 d

No history yet (it accumulates with the daily EPSS job).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • A low-privileged account is enough.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
high · data can be read
Integrity
high · data or configuration can be modified
Availability
high · the service can be disrupted
Attack vector
Network
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
High
Availability impact
High

Weakness class (CWE)

—

CVSS vector

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

nvd-primary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

No changes recorded on tracked fields yet. Score, KEV, exploit maturity and fix status changes appear here.

References

Show all references (1 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records