AWS patches Firecracker flaw that let privileged guests access VMM memory
AWS disclosed a flaw in Firecracker versions 0.23.0 through 1.16.1 that could let a root user inside a guest virtual machine read or modify the Firecracker process’s memory. AWS says exploitation requires a snapshot restored with the File memory backend, a balloon or virtio-mem device, and a host memory remapping failure; its managed services, including Lambda, are not affected.
Bottom line — Firecracker 1.16.2 and 1.17.0 contain the fix; AWS recommends the Uffd memory backend if an upgrade must wait.
Go deeper 5
-
AWS says the issue affects self-managed Firecracker deployments in the specified configuration; Lambda customers need take no action.
-
The flaw was found by Juan Pablo Martinez Kuhn of Coinspect, according to AWS.
-
AWS recommends upgrading to Firecracker 1.16.2 or 1.17.0 and later, and says operators maintaining forks should incorporate the fixes.
-
If an upgrade is not immediately possible, AWS recommends restoring snapshots with the Uffd memory backend, subject to its documented requirements.
-
CVETodo reports no public exploit and no CISA KEV listing as of 4 November 2026.