Security readout for executives and security teams
Plain-English summary
This flaw affects Cisco Firepower Management Center and can let a logged-in remote attacker overload the system by abusing XML entities in a dashboard widget. The expected impact is service disruption, not data theft or system takeover. Business urgency is moderate, especially where FMC manages critical firewall operations.
Executive priority
Schedule remediation through normal security maintenance unless FMC availability is operationally critical or many non-admin users have access. Prioritize access control review immediately because exploitation requires authentication.
Technical view
CVE-2021-1267 is an XML entity expansion issue in Cisco FMC dashboard widgets, mapped to CWE-776. An authenticated remote attacker with low privileges could craft an XML-based widget that drives elevated CPU and memory use, causing a denial-of-service condition. CVSS is 4.3, availability impact low.
Likely exposure
Exposure is limited to organizations running Cisco Firepower Management Center with authenticated users able to create or modify dashboard widgets. The source bundle does not provide affected version numbers, so asset owners must compare installed FMC releases against Cisco’s advisory.
Exploitation context
The source bundle describes authenticated remote exploitation and denial of service. It does not cite public exploitation, weaponized tooling, or CISA KEV listing. Treat active exploitation as unconfirmed based on the provided evidence.
Researcher notes
Evidence is strong for vulnerability class, affected product, attack precondition, and impact. Evidence is incomplete for exact affected versions, fixed releases, and vendor mitigations because those details are not included in the provided bundle.
Mitigation direction
- Review Cisco advisory for affected releases, fixed releases, and workarounds.
- Restrict FMC management access to trusted networks and administrators.
- Limit dashboard widget creation rights to users who need them.
- Monitor FMC CPU and memory for unexplained spikes.
- Investigate suspicious or newly created XML-based widgets.
Validation and detection
- Identify all deployed Cisco Firepower Management Center instances.
- Record FMC software versions and compare them with Cisco guidance.
- Review FMC user roles for widget creation or modification rights.
- Check monitoring history for CPU or memory exhaustion events.
- Review administrative activity for unexpected dashboard widget changes.
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-776: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. 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-2021-1267 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
- 4.3 (3.0)
- Known Exploited
- No
- Published
Vector: CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L
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:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L2.81.4Primary CVE scoreVulnerability scoring details
Base CVSS 3.0 score
4.3MediumVector: CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L
Source materials
- CVE List V5 sourceCVE List V5
- 20210113 Cisco Firepower Management Center XML Entity Expansion VulnerabilityCVE 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 Restriction of Recursive Entity References in DTDs ('XML Entity Expansion')
Improper Restriction of Recursive Entity References in DTDs ('XML Entity Expansion') represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.