GHSA-48ww-rqpp-2mgm · Runtime
NO FIX YET · SEE WHAT TO DO
Firecracker, the virtualization technology behind AWS Lambda, has a flaw in VMs restored from a snapshot that use the File memory backend with a balloon or virtio-mem device. Under certain host memory conditions, a root user inside the guest can read or modify memory of the Firecracker process.
first public Nov 4, 2026 · 1 source
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Exposure requires Firecracker v0.23.0 through v1.16.1, VMs restored from a snapshot, the File memory backend, and a balloon or virtio-mem device. Teams running self-hosted Firecracker microVMs should look at these settings. AWS states that Lambda and other AWS services are not affected and that no customer action is required for them.
Not affected if aws-managed-services, no-balloon-or-virtio-mem, no-snapshot-restore, uffd-backend
Who cares aws, firecracker, lab-disclosure, microvm, self-hosted, snapshot-restore
firecracker --version; versions v0.23.0 through v1.16.1 are affected.v1.16.2 or v1.17.0 or later.CVE-2026-122192: Guest Access to Firecracker Process Memory After a Failed Memory Discard
Bulletin ID: 2026-169-AWS Scope: AWS Content Type: Important (requires attention) Publication Date: 11/04/2026 11:30 AM PST
Description:
Firecracker is an open source virtualization technology that powers AWS Lambda and other serverless compute services. We identified CVE-2026-122192, an issue in Firecracker v0.23.0 through v1.16.1 that, under certain host memory conditions, can let a root user in a guest read or modify memory of the Firecracker process. It affects VMs restored from a snapshot using the File memory backend with a balloon or virtio-mem device.
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AWS services including AWS Lambda are not affected by this issue. No customer action is required.
Impacted versions: Firecracker v0.23.0 through v1.16.1, inclusive.
Within the currently supported release lines, v1.16.0 and v1.16.1 are affected. The fix is included in v1.16.2 and v1.17.0
Resolution:
This issue is fixed in Firecracker v1.16.2 and v1.17.0. If you restore VMs using the File memory backend with a balloon or virtio-mem device, we recommend upgrading to Firecracker v1.16.2, v1.17.0 or later. Operators maintaining forks or derivative code should incorporate the corresponding fixes.
Workarounds:
If upgrading is not immediately possible, restore snapshots using the Uffd memory backend, following its documented requirements for handling discarded pages.
The following measures address known host-memory failure conditions:
These measures do not prevent every replacement-mapping failure.
References:
Acknowledgement:
We thank Juan Pablo Martinez Kuhn from Coinspect for collaborating on this issue through the coordinated vulnerability disclosure process.
Please email [email protected] with any security questions or concerns.