CVE-2021-1572 | ConfD CLI Secure Shell Server Privilege Escalation Vulnerability

A vulnerability in ConfD could allow an authenticated, local attacker to execute arbitrary commands at the level of the account under which ConfD is running, which is commonly root. To exploit this vulnerability, an attacker must have a valid account on an affected device. The vulnerability exists because the affected software incorrectly runs the SFTP user service at the privilege level of the account that was running when the ConfD built-in Secure Shell (SSH) server for CLI was enabled. If the ConfD built-in SSH server was not enabled, the device is not affected by this vulnerability. An attacker with low-level privileges could exploit this vulnerability by authenticating to an affected device and issuing a series of commands at the SFTP interface. A successful exploit could allow the attacker to elevate privileges to the level of the account under which ConfD is running, which is commonly root. Note: Any user who can authenticate to the built-in SSH server may exploit this vulnerability. By default, all ConfD users have this access if the server is enabled. Software updates that address this vulnerability have been released.

Published: 2021-08-04 Last update: 2024-11-21 Assigner: [email protected] Source: [email protected]

Conclusion & alert: CVE-2021-1572 is rated Low Risk (36.8/100): CVSS High severity, with low exploitation likelihood (EPSS 0.25%). Mandatory action: Monitor for updates and reassess as exploit intelligence or EPSS changes.

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

Exploit prediction scoring system (EPSS) score for CVE-2021-1572

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 2026-06-15 0.11% 0.25% +0.14%
2 2025-11-21 0.05% 0.11% +0.06%
3 2025-11-18 0.05%

Full EPSS history (10 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-1572

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.8 3.1 HIGH
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H Click to expand
Attack vector (AV:L)
They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
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.
1.8 5.9 [email protected]
7.8 3.1 HIGH
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H Click to expand
Attack vector (AV:L)
They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
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.
1.8 5.9 [email protected]
6.9 2.0 MEDIUM
AV:L/AC:M/Au:N/C:C/I:C/A:C Click to expand
Access vector (AV:L)
Requires local access to the target system.
Access complexity (AC:M)
Exploitation needs some favorable conditions, but not exceptional ones.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:C)
Complete confidentiality impact.
Integrity impact (I:C)
Complete integrity impact.
Availability impact (A:C)
Complete availability impact.
3.4 10.0 [email protected]

Weakness enumeration for CVE-2021-1572

Affected software / configurations for CVE-2021-1572

Vendor Product Version Raw CPE
cisco confd >= 7.4, <= 7.4.3 cpe:2.3:a:cisco:confd:*:*:*:*:*:*:*:*
cisco confd >= 7.5, <= 7.5.2 cpe:2.3:a:cisco:confd:*:*:*:*:*:*:*:*
cisco network_services_orchestrator >= 5.4, <= 5.4.3.1 cpe:2.3:a:cisco:network_services_orchestrator:*:*:*:*:*:*:*:*
cisco network_services_orchestrator >= 5.5, <= 5.5.2.2 cpe:2.3:a:cisco:network_services_orchestrator:*:*:*:*:*:*:*:*

References for CVE-2021-1572

cvelogic Threat Intelligence