CVE-2025-66738
Privilege escalation on Yealink T21P_E2 IP Phone via ping diagnostic component.
Is CVE-2025-66738 being exploited?
Not confirmed. CVE-2025-66738 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked. EPSS currently estimates a 0.64% probability of exploitation in the next 30 days.
How severe is CVE-2025-66738?
CVE-2025-66738 is rated High with a CVSS score of 8.8. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2025-66738?
Not known from our data. No patch reference has been recorded for CVE-2025-66738, which is not the same as no patch existing — a fix may have shipped without a tagged reference, or after this record was written. The vendor advisory is the only authority on whether a fix exists, and mitigations may be available regardless.
What does CVE-2025-66738 affect?
CVE-2025-66738 affects Yealink T21P_E2 Phone. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2025-66738?
Update to latest firmware; disable or restrict diagnostic ping if feasible.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Remote attacker with normal privileges can execute arbitrary code via crafted ping requests in the diagnostic component.
Immediate action required