CVE-2021-42561

Exp

An issue was discovered in CALDERA 2.8.1. When activated, the Human plugin passes the unsanitized name parameter to a python "os.system" function. This allows attackers to use shell metacharacters (e.g., backticks "``" or dollar parenthesis "$()" ) in order to escape the current command and execute arbitrary shell commands.

Published: 2022-01-12 Last update: 2024-11-21 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2021-42561 is rated High Exploit Risk (87.7/100): CVSS High severity, with high exploitation likelihood (EPSS 10.29%, 93th percentile). 1 public exploit reference(s) are indexed (Exploit-DB). EPSS rose +7.28% over the last day, indicating growing attacker interest. 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-2021-42561

EDB-ID Source Kind Published Link
— nvd_ref exploit_tag Exploit-DB ↗

Exploit prediction scoring system (EPSS) score for CVE-2021-42561

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 2025-11-21 3.01% 10.29% +7.28%
2 2025-11-18 10.29% 3.01% -7.28%
3 2025-07-19 — 10.29% —

Full EPSS history (15 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-42561

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-2021-42561

Affected software / configurations for CVE-2021-42561

Vendor Product Version Raw CPE
mitre caldera <= 2.8.1 cpe:2.3:a:mitre:caldera:*:*:*:*:*:*:*:*

References for CVE-2021-42561

cvelogic Threat Intelligence