Security readout for executives and security teams
Plain-English summary
Cisco ISE had multiple web management interface XSS flaws. An attacker could trick an interface user into interacting with malicious content, potentially exposing limited data or changing limited interface state. This is not listed as known exploited in CISA KEV.
Executive priority
Treat as a scheduled security update unless the ISE management interface is broadly reachable or administrators face targeted phishing risk. It affects a security control plane, so delayed remediation increases governance risk.
Technical view
CVE-2021-40121 is a CWE-79 cross-site scripting issue in Cisco Identity Services Engine Software's web-based management interface. CVSS 3.1 is 6.1: network reachable, low complexity, no privileges, user interaction required, changed scope, low confidentiality and integrity impact, no availability impact.
Likely exposure
Exposure is most relevant where Cisco ISE administrators use the web management interface and can be targeted through links or embedded content. The source bundle does not identify affected release ranges.
Exploitation context
The vulnerability requires user interaction by a management interface user. The provided sources do not show active exploitation, public exploit use, or CISA KEV listing.
Researcher notes
Key missing detail is exact affected and fixed version data in the supplied bundle. Validation should focus on ISE presence, management interface reachability, administrator interaction risk, and vendor advisory version mapping.
Mitigation direction
- Review Cisco's advisory for affected releases and fixed software guidance.
- Prioritize remediation for internet-reachable or broadly accessible ISE management interfaces.
- Restrict management interface access to trusted administrative networks where feasible.
- Warn ISE administrators against untrusted links targeting management sessions.
Validation and detection
- Inventory Cisco ISE deployments and management interface exposure.
- Check installed ISE versions against Cisco's advisory guidance.
- Confirm administrative access is limited to intended users and networks.
- Review admin activity logs for unusual interface actions if exposure is suspected.
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-2021-40121 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
- 6.1 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/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:N/UI:R/S:C/C:L/I:L/A:N2.82.7Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
6.1MediumVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
Source materials
- CVE List V5 sourceCVE List V5
- 20211020 Cisco Identity Services Engine 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.