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CVE-2021-3929 is a use-after-free vulnerability in the NVMe controller emulation of QEMU, triggered by a DMA reentrancy issue. When a reentrant write operation causes the nvme_ctrl_reset() function to be invoked, certain data structures are freed while still in use, leading to a use-after-free condition. This flaw can be exploited by a malicious guest to crash the QEMU process or potentially execute arbitrary code on the host.
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1 valid exploit after Mallory filtered fakes, detection scripts, and README-only repos.
This repository is a proof-of-concept (PoC) exploit for CVE-2021-3929 and CVE-2021-3947, which are vulnerabilities in QEMU's emulation of NVMe and HDA devices. The exploit demonstrates a VM escape, allowing code execution on the QEMU host from a compromised guest. The main exploit logic is implemented in 'exp.c', which interacts with QEMU's emulated hardware via memory-mapped I/O (MMIO) regions, using hardcoded physical addresses for the NVMe and HDA devices. The exploit leverages these vulnerabilities to leak host memory addresses and ultimately execute an arbitrary command on the host (by default, launching '/usr/bin/gnome-calculator'). Supporting files include 'helpers.h' (utility functions for memory mapping and address translation) and 'qemu.h' (hardware structure definitions and constants). The README provides detailed setup instructions, including the required QEMU command line and guest configuration. The exploit is intended for educational purposes and requires a specific environment to function. No network endpoints are involved; the attack vector is local, requiring code execution within the guest VM.
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