CVE-2021-1582 | Cisco Application Policy Infrastructure Controller Stored Cross-Site Scripting Vulnerability

A vulnerability in the web UI of Cisco Application Policy Infrastructure Controller (APIC) or Cisco Cloud APIC could allow an authenticated, remote attacker to perform a stored cross-site scripting attack on an affected system. This vulnerability is due to improper input validation in the web UI. An authenticated attacker could exploit this vulnerability by sending malicious input to the web UI. A successful exploit could allow the attacker to execute arbitrary script code in the context of the web-based interface or access sensitive, browser-based information.

Published: 2021-08-25 Last update: 2024-11-21 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2021-1582 is rated Low Risk (33.8/100): CVSS Medium severity, with low exploitation likelihood (EPSS 0.17%). 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-2021-1582

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 2025-03-30 0.14% 0.17% +0.03%
2 2025-03-29 0.17% 0.14% -0.03%
3 2025-03-19 — 0.17% —

Full EPSS history (8 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-1582

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
5.4 3.1 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/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:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:L)
Some sensitive info could get out, but not a total data dump.
Integrity (I:L)
Attackers could change some data, but it’s limited—not everything goes.
Availability (A:N)
Service keeps running; no real outage angle.
 2.3 2.7 [email protected]
5.4 3.1 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/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:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:L)
Some sensitive info could get out, but not a total data dump.
Integrity (I:L)
Attackers could change some data, but it’s limited—not everything goes.
Availability (A:N)
Service keeps running; no real outage angle.
 2.3 2.7 [email protected]
3.5 2.0 LOW
AV:N/AC:M/Au:S/C:N/I:P/A:N Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:M)
Exploitation needs some favorable conditions, but not exceptional ones.
Authentication (AU:S)
A single authentication is required.
Confidentiality impact (C:N)
No confidentiality impact.
Integrity impact (I:P)
Partial integrity impact.
Availability impact (A:N)
No availability impact.
 6.8 2.9 [email protected]

Weakness enumeration for CVE-2021-1582

Affected software / configurations for CVE-2021-1582

Vendor Product Version Raw CPE
cisco application_policy_infrastructure_controller < 3.2\(10f\) cpe:2.3:a:cisco:application_policy_infrastructure_controller:*:*:*:*:*:*:*:*
cisco application_policy_infrastructure_controller >= 4.0, < 4.2\(7i\) cpe:2.3:a:cisco:application_policy_infrastructure_controller:*:*:*:*:*:*:*:*
cisco application_policy_infrastructure_controller >= 5.0, < 5.2\(2f\) cpe:2.3:a:cisco:application_policy_infrastructure_controller:*:*:*:*:*:*:*:*
cisco cloud_application_policy_infrastructure_controller < 3.2\(10f\) cpe:2.3:a:cisco:cloud_application_policy_infrastructure_controller:*:*:*:*:*:*:*:*
cisco cloud_application_policy_infrastructure_controller >= 4.0, < 4.2\(7i\) cpe:2.3:a:cisco:cloud_application_policy_infrastructure_controller:*:*:*:*:*:*:*:*
cisco cloud_application_policy_infrastructure_controller >= 5.0, < 5.2\(1h\) cpe:2.3:a:cisco:cloud_application_policy_infrastructure_controller:*:*:*:*:*:*:*:*

References for CVE-2021-1582

cvelogic Threat Intelligence