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CVE Record

CVE-2021-1606: 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 has stored XSS flaws in its web management interface. A logged-in administrator could place malicious script into certain interface pages, which may run when another user views them. Business risk is contained by the need for valid admin credentials, but ISE is security-critical infrastructure, so affected deployments should be checked promptly.

Executive priority

Treat this as a controlled but important security-platform maintenance item. It is not internet-scale unauthenticated risk, but compromise of ISE administration can affect sensitive security operations and identity infrastructure.

Technical view

CVE-2021-1606 is multiple stored XSS vulnerabilities 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 with network access, low attack complexity, high privileges required, user interaction required, changed scope, and low confidentiality and integrity impact.

Likely exposure

Exposure is limited to organizations running Cisco ISE with reachable administrative web interfaces. The attacker must already have valid administrative credentials, so the main concern is compromised, misused, or overly broad admin access.

Exploitation context

The source bundle does not report active exploitation, and the CVE is not marked KEV. Exploitation requires authenticated administrative access and a victim user interacting with affected stored content in the management interface.

Researcher notes

The key constraints are PR:H and UI:R. Validate exposure through version and management-plane review rather than offensive testing. The bundle does not include affected version ranges or fixed release details, so remediation should be anchored to Cisco's advisory.

Mitigation direction

  • Review Cisco's advisory for affected and fixed ISE releases.
  • Upgrade or apply Cisco-recommended remediation if your release is affected.
  • Restrict ISE management interface access to trusted administrative networks.
  • Review and reduce accounts with Cisco ISE administrative privileges.
  • Monitor Cisco guidance for any updated remediation details.

Validation and detection

  • Inventory Cisco ISE deployments and administrative interface exposure.
  • Compare installed ISE versions against Cisco's advisory guidance.
  • Review ISE administrator accounts for unexpected or excessive privileges.
  • Check administrative activity logs for suspicious interface changes.
  • Confirm no internal source claims exploitation without evidence.
Prepared
Confidence
medium
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-2021-1606 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-2021-1606Attack 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.