Security readout for executives and security teams
Plain-English summary
CVE-2021-1603 is a medium-severity stored XSS issue in Cisco ISE’s management interface. An attacker who already has valid administrative credentials could store malicious script in specific pages. If another user views it, the script could run in that user’s browser context and expose browser-based information.
Executive priority
Treat this as a controlled but real administrative-plane risk. It is not an unauthenticated takeover issue, but compromised or malicious admin accounts could use it to target other ISE users and sensitive browser-context data.
Technical view
Multiple CWE-79 input-validation flaws affect the Cisco Identity Services Engine Software web-based management interface. The CVSS 3.1 score is 4.8: network-reachable, low complexity, high privileges required, user interaction required, changed scope, low confidentiality and integrity impact, and no availability impact.
Likely exposure
Exposure is limited to Cisco ISE deployments where an attacker can authenticate to the management interface with administrative credentials. The provided source bundle does not specify affected or fixed version ranges.
Exploitation context
The source bundle does not report active exploitation, and this CVE is not listed as KEV. Practical exploitation requires valid administrative credentials and a victim user interacting with affected management-interface content.
Researcher notes
Evidence is limited to the CVE record and Cisco advisory reference. The bundle confirms product, vulnerability class, prerequisites, impact, CVSS vector, and non-KEV status, but does not include fixed versions, specific vulnerable pages, proof-of-concept status, or exploit telemetry.
Mitigation direction
- Review Cisco’s advisory for affected and fixed release guidance.
- Upgrade Cisco ISE according to vendor guidance where applicable.
- Limit Cisco ISE administrative access to trusted users only.
- Audit administrative accounts for unnecessary privileges.
- Monitor Cisco ISE management activity for suspicious stored content changes.
Validation and detection
- Inventory Cisco ISE deployments and exposed management interfaces.
- Confirm installed ISE versions against Cisco advisory guidance.
- Review admin account lists for stale or excessive privileges.
- Check whether management access is restricted to trusted networks.
- Review logs for unusual administrative changes to web-interface content.
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-2021-1603 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
- 4.8 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:H/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:H/UI:R/S:C/C:L/I:L/A:N1.72.7Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
4.8MediumVector: CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N
Source materials
- CVE List V5 sourceCVE List V5
- 20210707 Cisco Identity Services Engine Stored Cross-Site Scripting VulnerabilitiesCVE 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.
