Which versions of Firecracker are affected by CVE-2026-5747?

Amazon Firecracker versions 1.13.0 through 1.15.0 contain a memory corruption vulnerability in virtio PCI handling that allows compromised guest virtual machines to crash or take control of the host…. A patch is available.

How to fix or mitigate CVE-2026-5747?

Within 24 hours: Inventory all Firecracker deployments and identify instances running versions 1.13.0-1.15.0. Within 7 days: Upgrade to Firecracker version 1.14.4 (for 1.14.x branch) or 1.15.1 (for 1.15.x branch); defer new guest provisioning on affected versions pending upgrade completion. Within 30 days: Complete migration of all production workloads to patched versions and validate guest isolation through security testing.

Firecracker CVE-2026-5747

Q: What is the CVSS score of CVE-2026-5747?

CVE-2026-5747 has a CVSS 4.0 base score of 8.7 (High). CVSS vector: 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. EPSS exploitation probability: 0.0%.

HIGH

Divide By Zero (CWE-369)

2026-04-08 ff89ba41-3aa1-4d27-914a-91399e9639e5

Buffer Overflow RCE Firecracker

8.7

CVSS 4.0 · NVD

Severity by source

NVD PRIMARY

8.7 HIGH

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

SUSE

7.5 HIGH

AV:L/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:H

Primary rating from NVD.

CVSS VectorNVD

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

Attack Vector

Local

Attack Complexity

High

Privileges Required

High

User Interaction

None

Scope

Lifecycle Timeline

Re-analysis Queued

Apr 20, 2026 - 16:22 vuln.today

cvss_changed

Analysis Generated

Apr 08, 2026 - 00:22 vuln.today

CVE Published

Apr 08, 2026 - 00:16 nvd

HIGH 8.7

DescriptionCVE.org

An out-of-bounds write issue in the virtio PCI transport in Amazon 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.

To remediate this, users should upgrade to Firecracker 1.14.4 or 1.15.1 and later.

AnalysisAI

Memory corruption in Amazon Firecracker's virtio PCI transport (versions 1.13.0-1.14.3, 1.15.0) enables guest root users to crash the host VMM process or achieve host code execution through malicious virtio queue register modifications post-device activation. Affects x86_64 and aarch64 architectures. While exploitation requires guest root privileges and high attack complexity (CVSS AC:H, PR:H), successful compromise breaches VM isolation boundaries with high impact to host confidentiality, integrity, and availability (CVSS 8.7). No public exploit identified at time of analysis; vendor-released patches available in versions 1.14.4 and 1.15.1.

Technical ContextAI

This vulnerability exploits the virtio paravirtualization framework, specifically the PCI transport layer that manages I/O between guest VMs and the Firecracker VMM hypervisor. The out-of-bounds write (CWE-369: Divide By Zero mapping appears incorrect; likely CWE-787: Out-of-bounds Write based on description) occurs when a malicious guest manipulates virtio queue configuration registers after device activation. In normal operation, virtio devices follow a strict state machine where configuration occurs before activation; this flaw allows post-activation reconfiguration to write beyond allocated memory boundaries. Firecracker is Amazon's lightweight KVM-based microVM manager designed for serverless and container workloads, making VM escape vulnerabilities particularly critical in multi-tenant cloud environments. The vulnerability affects the core memory safety of the Rust-based VMM process running on the host, potentially allowing arbitrary code execution that completely breaks the VM isolation model.

RemediationAI

Upgrade immediately to Firecracker version 1.14.4 (for 1.13.x-1.14.x users) or 1.15.1 (for 1.15.0 users) or later versions. Release artifacts available at https://github.com/firecracker-microvm/firecracker/releases/tag/v1.14.4 and https://github.com/firecracker-microvm/firecracker/releases/tag/v1.15.1. No workarounds are documented; patching is the only effective mitigation. Organizations unable to patch immediately should restrict Firecracker deployments to trusted workloads only and avoid running untrusted guest kernels or snapshot configurations. Review security advisory at https://github.com/firecracker-microvm/firecracker/security/advisories/GHSA-776c-mpj7-jm3r for additional vendor guidance and impact assessment details.