CVE-2026-8718
Local kernel-heap overflow via getsockopt DTLS Connection ID in Zephyr
Is CVE-2026-8718 being exploited?
Not confirmed. CVE-2026-8718 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 0.12% probability of exploitation in the next 30 days.
How severe is CVE-2026-8718?
CVE-2026-8718 is rated High with a CVSS score of 8.4. 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-2026-8718?
Yes. A fix has been recorded for CVE-2026-8718. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-8718 affect?
CVE-2026-8718 affects Zephyr RTOS (>=v3.5.0) with CONFIG_MBEDTLS_SSL_DTLS_CONNECTION_ID, Zephyr CONFIG_USERSPACE builds with mbedTLS DTLS CID enabled, Embedded devices using Zephyr sockets+mbedTLS. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-8718?
Apply Zephyr patch that validates optlen; or disable DTLS CID / CONFIG_USERSPACE until patched
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Local unprivileged thread can trigger a kernel-heap buffer overflow (write up to 31 bytes) via getsockopt, enabling denial-of-service or local privilege escalation.
Patch when possible
- affected>= 3.5.0 and < 4.4.1
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.