Out-of-Bounds Write in virtio PCI Transport (Firecracker <=1.15.0)
CVE-2026-5747 Published on April 7, 2026
Out-of-bounds Write in Firecracker virtio-pci Transport
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.
Vulnerability Analysis
CVE-2026-5747 can be exploited with local system access, and requires user privileges. This vulnerability is consided to have a high level of attack complexity. The potential impact of an exploit of this vulnerability is considered to be very high.
Weakness Types
What is a Memory Corruption Vulnerability?
The software writes data past the end, or before the beginning, of the intended buffer. Typically, this can result in corruption of data, a crash, or code execution. The software may modify an index or perform pointer arithmetic that references a memory location that is outside of the boundaries of the buffer. A subsequent write operation then produces undefined or unexpected results.
CVE-2026-5747 has been classified to as a Memory Corruption vulnerability or weakness.
Divide By Zero
The product divides a value by zero. This weakness typically occurs when an unexpected value is provided to the product, or if an error occurs that is not properly detected. It frequently occurs in calculations involving physical dimensions such as size, length, width, and height.
Products Associated with CVE-2026-5747
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Affected Versions
AWS Firecracker:- Version 1.13.0, <= 1.14.3 is affected.
- Version 1.15.0 is affected.
- Version 1.14.4 is unaffected.
- Version 1.15.1 is unaffected.
Exploit Probability
EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.