LiveActive security incident?Get immediate response
CVE Record

CVE-2021-1603: Cisco Identity Services Engine Stored Cross-Site Scripting Vulnerabilities

Multiple vulnerabilities in the web-based management interface of Cisco Identity Services Engine (ISE) could allow an authenticated, remote attacker to conduct a stored cross-site scripting (XSS) attack against a user. These vulnerabilities exist because the web-based management interface does not sufficiently validate user-supplied input. An attacker could exploit these vulnerabilities by injecting malicious code into specific pages of the interface. A successful exploit could allow the attacker to execute arbitrary script code in the context of the affected interface or access sensitive, browser-based information. To exploit these vulnerabilities, the attacker would need valid administrative credentials.

MediumCVSS 4.8Not KEV-listedUpdated
Glexia's TakeAutomated analysismoderate

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.
Prepared
Confidence
high
Sources
3

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

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 · medium confidence lookup

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 lookup
cve · low confidence lookup

CVE-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
Vulnerability profileCVE Program record
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

Official CVE source material

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.

1CVSS vectors
0Timeline events
0ADP providers
2Source links

CVSS vector scores

1 official score

We 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.

ScoreVersionSeverityVectorExploitImpactSource
4.8CVSS 3.1MediumCVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N1.72.7Primary CVE score

Vulnerability scoring details

Base CVSS 3.1 score

4.8Medium
CVSS 3.1 vector shape for CVE-2021-1603Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Privileges Required
NoneLowHigh
User Interaction
NoneRequired
Scope
ChangedUnchanged
Confidentiality Impact
HighLowNone
Integrity Impact
HighLowNone
Availability Impact
HighLowNone

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
CiscoCisco Identity Services Engine Softwaren/aListed
Weakness

CWE details

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.

CWE-79 · source CWE mapping

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.