Security readout for executives and security teams
Plain-English summary
Cisco FMC’s web management interface had vulnerabilities that could let a highly privileged attacker trigger XSS or redirect a user to another site. Business urgency is moderate because exploitation requires admin-level access and user interaction, but FMC is a security control plane and should be treated carefully.
Executive priority
Treat this as a scheduled security-control-plane remediation, not an emergency unless FMC management is broadly exposed. The main risk is abuse of trusted administrators or management sessions rather than unauthenticated takeover.
Technical view
CVE-2021-34763 covers Cisco FMC web interface XSS and open redirect issues. The CVSS 3.1 score is 4.8 with network access, low complexity, high privileges, required user interaction, changed scope, low confidentiality and integrity impact, and no availability impact.
Likely exposure
Exposure is limited to organizations running Cisco Firepower Management Center Software. The bundle does not identify affected version ranges, so teams must verify deployed FMC versions against Cisco’s advisory and their asset inventory.
Exploitation context
The provided sources do not show CISA KEV listing or active exploitation. The CVSS vector indicates an attacker needs high privileges and must induce user interaction, reducing broad internet-scale risk but not eliminating targeted administrative risk.
Researcher notes
The evidence supports XSS and open redirect in the FMC web interface, mapped to CWE-601 in the bundle. Affected versions and exact fixed releases are not included here, so avoid assuming scope beyond Cisco FMC Software and consult Cisco’s advisory for version-specific decisions.
Mitigation direction
- Check Cisco’s advisory for fixed software or vendor-recommended remediation.
- Prioritize remediation for internet-reachable or broadly accessible FMC management interfaces.
- Restrict FMC administrative access to trusted networks and authorized administrators.
- Review administrative account hygiene and remove unnecessary high-privilege access.
Validation and detection
- Inventory all Cisco FMC deployments and record software versions.
- Compare deployed versions with Cisco’s advisory for CVE-2021-34763.
- Confirm FMC management interfaces are not exposed beyond intended administrative networks.
- Review logs for suspicious administrative web activity or unexpected redirects.
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-601: 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-2021-34763 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
- 20211027 Cisco Firepower Management Center Software Cross-Site Scripting and Open Redirect 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.
URL Redirection to Untrusted Site ('Open Redirect')
URL Redirection to Untrusted Site ('Open Redirect') represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.