Guest-to-host escape in widely used Oracle VM VirtualBox (high CVSS). Host compromise from untrusted guests risks broad operational impact and warrants company-wide notice.
CVE-2026-77178
VirtualBox PCNet OOB write allows guest-to-host compromise
Is CVE-2026-77178 being exploited?
Not confirmed. CVE-2026-77178 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 0.34% probability of exploitation in the next 30 days.
How severe is CVE-2026-77178?
CVE-2026-77178 is rated Critical with a CVSS score of 9.1. 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-2026-77178?
Yes. A fix has been recorded for CVE-2026-77178. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-77178 affect?
CVE-2026-77178 affects Oracle VM VirtualBox < 7.2.8, PCNet (Am79C970A) device model (DevPCNet.cpp). Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-77178?
Update VirtualBox to 7.2.8+; avoid untrusted guests and restrict host network access
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Local guest triggers out-of-bounds write in host via PCNet, enabling host crash or arbitrary code execution (guest-to-host escape).
Immediate action required