CVE-2026-122192 · Infrastructure
NO FIX YET · SEE WHAT TO DO
Firecracker is an open source virtualization technology used by AWS Lambda. Under certain host memory conditions, a root user inside a guest VM restored from a snapshot can read or modify memory of the Firecracker process.
first public Nov 4, 2026 · 2 sources
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Teams that run Firecracker microVMs themselves and restore VMs from snapshots using the File memory backend with a balloon or virtio-mem device. AWS states its own services, including Lambda, are not affected and need no customer action. Teams using the Uffd memory backend for snapshot restore are outside the stated scope.
Not affected if managed-hosting, no-balloon-or-virtio-mem, no-snapshot-restore, uffd-backend
Who cares aws, firecracker, lab-disclosure, microvm, self-hosted
firecracker --version; affected versions are v0.23.0 through v1.16.1.sysctl vm.overcommit_memory and the kernel version with uname -r.v1.16.2 or (or later).v1.17.0CVE-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.
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.
This page as .md · .json · in your agent: get_signal("CVE-2026-122192") · CVSS:4.0/AV:L/AC:L/AT:P/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/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
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