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CVE Record

CVE-2021-1604: 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

Cisco ISE's admin web interface can store malicious script input from an authenticated administrator. If another user later views an affected page, script could run in that user's browser session and expose browser-based information or alter interface content. Severity is moderate because exploitation needs valid administrative credentials and user interaction, but ISE is security-critical infrastructure.

Executive priority

Treat as a scheduled remediation item unless ISE administration is broadly exposed or administrator account control is weak. Prioritize validation because ISE supports identity and access control, and compromise of admin browser sessions could affect security operations.

Technical view

CVE-2021-1604 is stored XSS in Cisco Identity Services Engine Software caused by insufficient validation of user-supplied input in the web management interface. CVSS 3.1 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 Identity Services Engine deployments where administrative users can access the web-based management interface. The source bundle does not identify specific affected or fixed versions, so teams must confirm applicability against Cisco's advisory and local ISE inventory.

Exploitation context

The provided sources do not state active exploitation, and the CVE is not marked KEV. Exploitation requires valid administrative credentials and a victim user viewing the stored content. This reduces broad internet-scale risk but still matters where administrator accounts, shared consoles, or delegated admin roles are exposed.

Researcher notes

Evidence supports stored XSS requiring authenticated administrative access. The bundle does not provide affected version ranges, fixed releases, proof of exploitation, or detailed vulnerable pages. Avoid assuming exploitability beyond the stated management-interface stored XSS behavior.

Mitigation direction

  • Review Cisco's advisory for affected releases and vendor-approved fixes.
  • Inventory Cisco ISE deployments and record software versions.
  • Restrict ISE management interface access to trusted networks and administrators.
  • Review administrative account access and remove unnecessary privileges.
  • Monitor Cisco guidance before applying compensating controls or upgrades.

Validation and detection

  • Confirm whether Cisco ISE Software is deployed in the environment.
  • Compare installed ISE versions against Cisco's advisory.
  • Verify management interface access is restricted to authorized administrators.
  • Review admin roles for unnecessary high-privilege access.
  • Check browser and audit logs for suspicious admin-console activity.
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-2021-1604 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-2021-1604Attack 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.