CVE-2021-1261 | Cisco SD-WAN Command Injection Vulnerabilities

Multiple vulnerabilities in Cisco SD-WAN products could allow an authenticated attacker to perform command injection attacks against an affected device, which could allow the attacker to take certain actions with root privileges on the device. For more information about these vulnerabilities, see the Details section of this advisory.

Published: 2021-01-20 Last update: 2026-06-16 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2021-1261 is rated Moderate Risk (55.6/100): CVSS High severity, with medium exploitation likelihood (EPSS 1.43%). Review affected assets and schedule remediation.

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-2021-1261

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 1.28% 1.43% +0.15%
2 2025-11-21 1.45% 1.28% -0.17%
3 2025-11-18 — 1.45% —

Full EPSS history (13 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-1261

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]
8.1 3.0 HIGH
CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N 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:N)
Service keeps running; no real outage angle.
 2.8 5.2 [email protected]
7.2 2.0 HIGH
AV:L/AC:L/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:L)
Exploitation conditions are straightforward and predictable.
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.
 3.9 10.0 [email protected]

Weakness enumeration for CVE-2021-1261

Affected software / configurations for CVE-2021-1261

Vendor Product Version Raw CPE
cisco sd-wan_firmware 18.2.0 cpe:2.3:o:cisco:sd-wan_firmware:18.2.0:*:*:*:*:*:*:*
cisco sd-wan_firmware 18.3.0 cpe:2.3:o:cisco:sd-wan_firmware:18.3.0:*:*:*:*:*:*:*
cisco sd-wan_firmware 18.3.8 cpe:2.3:o:cisco:sd-wan_firmware:18.3.8:*:*:*:*:*:*:*
cisco sd-wan_firmware 18.4.6 cpe:2.3:o:cisco:sd-wan_firmware:18.4.6:*:*:*:*:*:*:*
cisco sd-wan_firmware 19.2.3 cpe:2.3:o:cisco:sd-wan_firmware:19.2.3:*:*:*:*:*:*:*
cisco sd-wan_firmware 19.2.99 cpe:2.3:o:cisco:sd-wan_firmware:19.2.99:*:*:*:*:*:*:*
cisco sd-wan_firmware 20.1.0 cpe:2.3:o:cisco:sd-wan_firmware:20.1.0:*:*:*:*:*:*:*
cisco sd-wan_vsmart_controller_firmware — cpe:2.3:o:cisco:sd-wan_vsmart_controller_firmware:*:*:*:*:*:*:*:*
cisco catalyst_sd-wan_manager — cpe:2.3:a:cisco:catalyst_sd-wan_manager:-:*:*:*:*:*:*:*
cisco sd-wan_vbond_orchestrator — cpe:2.3:a:cisco:sd-wan_vbond_orchestrator:-:*:*:*:*:*:*:*

References for CVE-2021-1261

cvelogic Threat Intelligence