Executive brief
Bitdefender Napoca is a bare-metal hypervisor used to manage and isolate virtual machine environments. A security flaw allows a user on a guest virtual machine to write data into the hypervisor's private memory. This could lead to a complete takeover of the host system or a total service outage. Because the product is end-of-life, no security updates will be released, and users are advised to stop using the software.
Technical details
An out-of-bounds write vulnerability exists in the real-mode hook handler of Bitdefender Napoca, specifically within 'napoca/kernel/handler.c'. The vulnerability stems from a lack of bounds validation on a guest-controlled SS:SP-derived offset used to index the 1MB RealModeMemory buffer. By providing specific register values (SS=0xFFFF, ESP=0xFFFF), an attacker can calculate an offset of 0x10FFEF, which exceeds the buffer by over 65,000 bytes. This allows an IRET frame push to overwrite the hypervisor's heap memory. An attacker with local access to a guest VM can exploit this to achieve arbitrary code execution at the hypervisor level. No patch is available as the product is end-of-life.
Affected products
- Bitdefender Napoca All versions (End-of-Life)
Timeline
- 2026-06-02: disclosed
- 2026-06-02: advisory