Security readout for executives and security teams
Plain-English summary
CVE-2021-1582 is a stored cross-site scripting issue in the Cisco APIC or Cisco Cloud APIC web UI. An authenticated attacker could store malicious input that later runs script in another user’s browser, potentially exposing browser-based information or altering UI actions.
Executive priority
Treat this as a moderate operational risk for APIC environments. It is not evidenced as actively exploited, but it affects a management interface where browser-session exposure or UI manipulation could matter.
Technical view
The vulnerability is CWE-79 caused by improper input validation in the web UI. The CVSS 3.1 score is 5.4 with network access, low attack complexity, low privileges required, user interaction required, changed scope, and low confidentiality and integrity impact.
Likely exposure
Exposure is most likely where Cisco APIC or Cisco Cloud APIC web UI access is available to authenticated users. The source bundle does not provide affected version ranges, so version-specific exposure requires checking Cisco’s advisory.
Exploitation context
The provided sources do not indicate known active exploitation, and the CVE is not marked KEV. Exploitation requires an authenticated attacker and another user interacting with the affected web interface.
Researcher notes
Evidence is limited to the CVE record and Cisco advisory reference. The bundle does not include fixed-version details, exploit observations, or product version ranges, so remediation validation should anchor on Cisco’s current advisory.
Mitigation direction
- Review Cisco’s advisory for affected versions and fixed releases.
- Apply vendor-supported updates once confirmed for the deployed version.
- Limit APIC web UI access to trusted administrative users and networks.
- Review user roles with access to APIC web UI input fields.
Validation and detection
- Inventory Cisco APIC and Cisco Cloud APIC deployments.
- Compare deployed versions against Cisco’s advisory.
- Confirm the APIC web UI is not broadly reachable.
- Review audit logs for suspicious authenticated UI changes.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-79: User-session and phishing behavior lookup
Client-side and session-facing weaknesses should be reviewed alongside initial-access and user-execution behaviors. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCVE-2021-1582 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Medium
- CVSS
- 5.4 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N2.32.7Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
5.4MediumVector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
Source materials
- CVE List V5 sourceCVE List V5
- 20210825 Cisco Application Policy Infrastructure Controller Stored Cross-Site Scripting VulnerabilityCVE reference · vendor-advisory, x_refsource_CISCO
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.