CVE-2021-33393

Exp

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.

Published: 2021-06-09 Last update: 2026-06-16 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2021-33393 is rated High Exploit Risk (85.1/100): CVSS High severity, with high exploitation likelihood (EPSS 58.73%, 99th percentile). 3 public exploit reference(s) are indexed (Exploit-DB). Public exploits are available—assess exposure, apply mitigations, and prioritize patching.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Public exploit references (Exploit-DB) for CVE-2021-33393

EDB-ID Source Kind Published Link
49869 exploit_db edb 2021-05-17 Exploit-DB ↗
— nvd_ref exploit_tag Exploit-DB ↗
— nvd_ref exploit_tag Exploit-DB ↗

Exploit prediction scoring system (EPSS) score for CVE-2021-33393

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-22 58.45% 58.73% +0.27%
2 2026-06-15 72.18% 58.45% -13.73%
3 2026-01-29 — 72.18% —

Full EPSS history (43 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-33393

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
8.8 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 2.8 5.9 [email protected]
9.0 2.0 HIGH
AV:N/AC:L/Au:S/C:C/I:C/A:C Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:S)
A single authentication is required.
Confidentiality impact (C:C)
Complete confidentiality impact.
Integrity impact (I:C)
Complete integrity impact.
Availability impact (A:C)
Complete availability impact.
 8.0 10.0 [email protected]

Weakness enumeration for CVE-2021-33393

Affected software / configurations for CVE-2021-33393

Vendor Product Version Raw CPE
ipfire ipfire < 2.25 cpe:2.3:a:ipfire:ipfire:*:*:*:*:*:*:*:*
ipfire ipfire 2.25 cpe:2.3:a:ipfire:ipfire:2.25:core_update141:*:*:*:*:*:*
ipfire ipfire 2.25 cpe:2.3:a:ipfire:ipfire:2.25:core_update142:*:*:*:*:*:*
ipfire ipfire 2.25 cpe:2.3:a:ipfire:ipfire:2.25:core_update143:*:*:*:*:*:*
ipfire ipfire 2.25 cpe:2.3:a:ipfire:ipfire:2.25:core_update144:*:*:*:*:*:*
ipfire ipfire 2.25 cpe:2.3:a:ipfire:ipfire:2.25:core_update145:*:*:*:*:*:*
ipfire ipfire 2.25 cpe:2.3:a:ipfire:ipfire:2.25:core_update146:*:*:*:*:*:*
ipfire ipfire 2.25 cpe:2.3:a:ipfire:ipfire:2.25:core_update147:*:*:*:*:*:*
ipfire ipfire 2.25 cpe:2.3:a:ipfire:ipfire:2.25:core_update148:*:*:*:*:*:*
ipfire ipfire 2.25 cpe:2.3:a:ipfire:ipfire:2.25:core_update149:*:*:*:*:*:*
ipfire ipfire 2.25 cpe:2.3:a:ipfire:ipfire:2.25:core_update150:*:*:*:*:*:*
ipfire ipfire 2.25 cpe:2.3:a:ipfire:ipfire:2.25:core_update151:*:*:*:*:*:*
ipfire ipfire 2.25 cpe:2.3:a:ipfire:ipfire:2.25:core_update152:*:*:*:*:*:*
ipfire ipfire 2.25 cpe:2.3:a:ipfire:ipfire:2.25:core_update155:*:*:*:*:*:*
ipfire ipfire 2.25 cpe:2.3:a:ipfire:ipfire:2.25:core_update156:*:*:*:*:*:*

References for CVE-2021-33393

cvelogic Threat Intelligence