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.

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:

• On kernels without the Linux 6.12 overcommit-handling change, use heuristic overcommit (vm.overcommit_memory=0) and keep the maximum discard size no greater than the host’s total RAM plus swap.
• Keep the memory cgroup’s out-of-memory (OOM) killer enabled.

These measures do not prevent every replacement-mapping failure.

References:

• CVE-2026-122192
• GHSA-48ww-rqpp-2mgm

Acknowledgement:

We thank Juan Pablo Martinez Kuhn from Coinspect for collaborating on this issue through the coordinated vulnerability disclosure process.

Please email aws-security@amazon.com with any security questions or concerns.