CVE-2026-97997

/// Technical description

In the Linux kernel, the following vulnerability has been resolved:

virtio_ring: fix stale descriptor flags after a failed packed add

In a packed ring the AVAIL and USED bits sit in the descriptor itself,

so writing them makes that descriptor available. Those bit combinations

flip meaning on every round of the ring, tracked by a wrap counter, so

invalidating or validating a descriptor means inverting both bits.

Commit 1ce9e6055fa0 ("virtio_ring: introduce packed ring support") has

virtqueue_add_packed() make every descriptor of a chain available as it

maps the chain, and write the head last. The device consumes the ring in

order and stops at a head that is not available yet, so it never reaches

the rest.

When vring_map_one_sg() fails partway, unmap_release unmaps the segments

and restores avail_used_flags, but the descriptors it wrote to in the

ring stay marked with AVAIL and USED bits. The head is now the only

entry that keeps the device from consuming these stale entries.

For ex

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References