Security readout for executives and security teams
Plain-English summary
Cisco Meeting Server has an API flaw that can let a logged-in remote attacker disrupt meetings. A successful attack could disconnect all participants from a call. This is not described as data theft or system takeover, but it can interrupt business communications.
Executive priority
Moderate priority. The issue can disrupt meetings but does not show confidentiality or integrity impact in the supplied sources. Raise urgency if Cisco Meeting Server supports executive, customer, or incident-response communications.
Technical view
CVE-2021-1524 is a CWE-20 improper input validation issue in the Cisco Meeting Server API. The CVSS 3.1 score is 4.3. The attack requires network access, low privileges, and no user interaction. Impact is limited to availability disruption.
Likely exposure
Exposure is likely limited to organizations running Cisco Meeting Server where the API is reachable by authenticated users. The source bundle does not provide affected release numbers, so teams must verify versions against Cisco’s advisory.
Exploitation context
The provided sources do not indicate active exploitation, and the CVE is not listed as KEV. Exploitation requires authentication to the API and a malicious request, with the reported result being call participant disconnection.
Researcher notes
Do not treat this as unauthenticated access, remote code execution, or data exposure based on current evidence. The key uncertainty is exact affected and fixed versions, which are not included in the source bundle.
Mitigation direction
- Review Cisco’s advisory for affected releases and fixed software guidance.
- Restrict Cisco Meeting Server API access to trusted administrative networks.
- Limit API-capable accounts to users with a business need.
- Monitor Cisco Meeting Server availability and meeting-disconnect anomalies.
- Prioritize remediation for environments relying on meetings for operations.
Validation and detection
- Inventory Cisco Meeting Server deployments and API exposure points.
- Compare deployed versions against Cisco’s advisory.
- Review which accounts can authenticate to the API.
- Check logs for unusual authenticated API activity around call drops.
- Confirm operational teams can detect meeting-wide disconnections.
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-20: 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-2021-1524 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 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/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:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L2.81.4Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
4.3MediumVector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L
Source materials
- CVE List V5 sourceCVE List V5
- 20210616 Cisco Meeting Server API Denial of Service 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 Input Validation
Improper Input Validation represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.