CVE-2026-64456: hwrng: virtio: clamp device-reported used.len at copy_data()
hwrng: virtio: clamp device-reported used.len at copydata()
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 6.6.145.2-1 - Upgrade
Upgrade
Linux kernel virtio-rngto a version that resolves this vulnerability.Patch hwrng: virtio: clamp device-reported used.len at copy_data() - Configuration
Disable virtio-rng entirely on the affected guests/hosts to narrow the vulnerable code path (the text notes: “disable virtio-rng entirely, so this path is narrow”).
virtio-rng (hwrng) disable virtio-rng = entirely - Compensating control
Limit/avoid access to the guest RNG leak channel: because confidential-compute guests can probe /dev/hwrng as a leak channel, restrict or monitor access to /dev/hwrng for guest root/userspaces if feasible in your environment.
Event History
Frequently Asked Questions
What is the severity of CVE-2026-64456?
CVE-2026-64456 has a high severity rating of 7.7 according to the CVSS 3.1 score.
How do I fix CVE-2026-64456?
To mitigate CVE-2026-64456, ensure you update to a patched version of the Linux kernel that addresses this vulnerability.
What components are affected by CVE-2026-64456?
CVE-2026-64456 affects the virtio random number generator component within the Linux kernel.
What attack vector does CVE-2026-64456 involve?
CVE-2026-64456 involves a local attack vector, allowing unauthorized access to sensitive data.
What type of vulnerability is CVE-2026-64456?
CVE-2026-64456 is categorized as an integer overflow vulnerability in the device-reported used length handling.