CVE-2025-36939
OpenThread MLE parsing flaws allow authenticated local attacker to crash or overflow Thread devices.
Is CVE-2025-36939 being exploited?
Not confirmed. CVE-2025-36939 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 0.23% probability of exploitation in the next 30 days.
How severe is CVE-2025-36939?
CVE-2025-36939 is rated Critical with a CVSS score of 10.0. 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-2025-36939?
Not known from our data. No patch reference has been recorded for CVE-2025-36939, 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-2025-36939 affect?
CVE-2025-36939 affects OpenThread library, Thread-enabled IoT and Matter devices, Device firmware using OpenThread. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2025-36939?
Apply vendor firmware updates ASAP; isolate Thread networks and restrict local access.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Authenticated attacker on the same Thread network can trigger assertion failures and a stack-based buffer overflow causing DoS and possible remote code execution on devices.
Immediate action required
- affected3.78.518349
As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.