Security readout for executives and security teams
Plain-English summary
This CVE describes a command injection issue in the Yealink T21P_E2 phone firmware 52.84.0.15. A remote attacker with normal privileges could abuse the diagnostic ping function to execute arbitrary code. That creates business risk to voice infrastructure confidentiality, integrity, and availability.
Executive priority
Prioritize remediation planning for affected phones, especially in environments where voice devices are reachable from broad internal networks. Treat this as high urgency, but do not assume active exploitation from the provided evidence.
Technical view
The record maps to CWE-77 and CVSS 3.1 score 8.8: network attack vector, low complexity, low privileges required, no user interaction, and high impact across confidentiality, integrity, and availability. The described trigger is a crafted request to the diagnostic component’s ping function.
Likely exposure
Organizations using Yealink T21P_E2 phones on firmware 52.84.0.15 may be exposed. Exposure is more likely where authenticated users can reach phone management or diagnostic functions over the network. The CVE affected-product metadata is incomplete, so validate by model and firmware rather than CPE alone.
Exploitation context
The source bundle does not show CISA KEV listing or cited evidence of active exploitation. The vulnerability still has practical risk because it is network-reachable, low-complexity, and only requires normal privileges according to the CVSS vector.
Researcher notes
The public record provides a concise vulnerability description, CVSS vector, CWE-77 classification, and one Google Drive reference. Product metadata is incomplete in the affected array, and no patch details are included in the supplied sources.
Mitigation direction
- Check Yealink guidance for fixed firmware or official mitigation.
- Inventory Yealink T21P_E2 phones and firmware versions.
- Restrict phone management interfaces to trusted administration networks.
- Disable or limit diagnostic access where operationally feasible.
- Review account privileges for phone administration users.
- Monitor for unusual diagnostic or management requests.
Validation and detection
- Confirm whether Yealink T21P_E2 devices are present.
- Record firmware versions, especially 52.84.0.15.
- Identify who can access diagnostic ping functionality.
- Verify management interfaces are not internet-exposed.
- Track CVE and vendor advisories for remediation updates.
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-77: Command execution behavior lookup
Command injection weaknesses can lead defenders to review execution techniques and command interpreter telemetry. 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-2025-66738 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
- High
- CVSS
- 8.8 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
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.
SSVC decision data
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:H/I:H/A:H2.85.9CISA-ADPVulnerability scoring details
Base CVSS 3.1 score
8.8HighVector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Vulnerability timeline
Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.
- CVE reservedCVE Program
The CVE ID was reserved by the assigning CNA.
- CVE publishedCVE Program
The CVE record was published.
- CVE updatedCVE Program
The CVE record metadata indicates this as the latest update time.
ADP provider summaries
Source materials
- CVE List V5 sourceCVE List V5
- https://drive.google.com/file/d/13t5ywSPJMx4487njJcH3ZTNuc_k3h4ty/view?usp=sharingCVE reference, mitre
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 Special Elements used in a Command ('Command Injection')
Improper Neutralization of Special Elements used in a Command ('Command Injection') represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.