Security readout for executives and security teams
Plain-English summary
This flaw affects Cisco Expressway Series and Cisco TelePresence VCS management interfaces. An administrator account could upload a specially crafted software image and make the appliance run code as root. The attacker already needs high privileges, but a successful compromise could give full operating-system control of a collaboration edge system.
Executive priority
Treat as a medium-priority remediation item unless the appliance is internet-exposed or has weak administrative controls. The business concern is full device compromise after administrator-level access, not unauthenticated mass exploitation based on the supplied evidence.
Technical view
CVE-2021-34716 is an authenticated remote code execution issue caused by incorrect handling of crafted software images uploaded through the web-based management interface. The CVSS 3.1 score is 6.7 with high confidentiality and integrity impact, high privileges required, no user interaction, and limited availability impact.
Likely exposure
Exposure is likely limited to organizations running Cisco Expressway Series or Cisco TelePresence Video Communication Server appliances where administrative web management is reachable. The source bundle does not provide affected software version ranges.
Exploitation context
Sources describe exploitation by an authenticated administrative user uploading crafted software images. The CVE is not listed as KEV in the bundle, and no cited source here establishes active exploitation.
Researcher notes
The key constraints are PR:H and the software-image upload path. Focus validation on affected Cisco appliance presence, management-plane reachability, administrator account governance, and vendor version applicability. The supplied sources do not include exploit code, exploitation telemetry, or detailed fixed-version data.
Mitigation direction
- Review Cisco advisory cisco-sa-ewrce-QPynNCjh for official fixed release and upgrade guidance.
- Inventory Cisco Expressway Series and TelePresence VCS appliances in the environment.
- Limit administrative management access to trusted users and networks where operationally feasible.
- Check vendor guidance before relying on compensating controls.
Validation and detection
- Match deployed products and versions against the Cisco advisory.
- Confirm web-based management exposure for affected appliances.
- Review administrative activity for unexpected software image uploads.
- Verify only authorized administrators can upload software images.
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-460: 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 lookupExecution behavior lookup
The CVE wording references code or command execution, so execution technique review may help defensive triage. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2021-34716 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
- 6.7 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/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:H/UI:N/S:U/C:H/I:H/A:L1.25.5Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
6.7MediumVector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:L
Source materials
- CVE List V5 sourceCVE List V5
- 20210818 Cisco Expressway Series and TelePresence Video Communication Server Remote Code Execution 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 Cleanup on Thrown Exception
Improper Cleanup on Thrown Exception represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.