CVE-2026-10046: Bitdefender Napoca bare-metal hypervisor contains an out-of-bounds write vulnerability in the BIOS INT 0x15 / E820 memory map handler, implemented in napoca/gue

Bitdefender Napoca bare-metal hypervisor contains an out-of-bounds write vulnerability in the BIOS INT 0x15 / E820 memory map handler, implemented in napoca/gue

Bitdefender Napoca bare-metal hypervisor contains an out-of-bounds write vulnerability in the BIOS INT 0x15 / E820 memory map handler, implemented in napoca/guests/bios_handlers.c. The handler computes a destination offset into the guest RealModeMemory buffer from guest-controlled ES and EDI register values without validating that the resulting address remains within the 1MB RealModeMemory allocation. A malicious guest operating in real mode can trigger the issue by invoking INT 0x15 with AX=0xE820, EDX=0x534D4150, ECX greater than or equal to 20, EBX=0, ES=0xFFFF, and EDI=0xFFFF. This can cause a write of up to 20 bytes past the end of the RealModeMemory buffer into the hypervisor heap. The product is end-of-life and unsupported when assigned.

Description from the National Vulnerability Database, published by cve-requests@bitdefender.com

What it means for a small business

If your business uses Napoca bare-metal hypervisor, install the vendor's update. If you're not sure whether you use it, ask whoever manages your computers.

How likely is an attack? The Exploit Prediction Scoring System, run by FIRST (the global association of security response teams), puts the odds of this one being exploited in the next 30 days at 0.12%, higher than 1% of CVEs. That’s low, but low isn’t zero, and the odds jump the day someone publishes an exploit. Scored October 29, 2026, updated daily.

Check your own setup

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Server check: what your web server says about itself, and whether that version has known flaws.

Sources

Part of the Huttenlocher Technologies vulnerability database, refreshed twice a day from CISA and the NVD. The title, category and plain-language guidance are ours; check the linked record before acting on a detail. This is general guidance, not a review of your systems.

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