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CVE-2026-97991: Product identification pending

Severity

7.8 (HIGH)

Patch status

Unknown

Published

2026-09-25T11:17:27.220

Modified

2026-09-25T15:18:03.453

Why it matters

High-severity vulnerability requiring prioritized review.

Recommended admin actions

• Review and patch based on exposure, asset criticality, and business impact.
• Compare installed versions against the affected version range in the advisory.

Technical summary

In the Linux kernel, the following vulnerability has been resolved: vdpa_sim_blk: reject out-of-range sector starts vdpasim_blk_check_range() logs an invalid start sector but continues validating the request. The subsequent unsigned capacity subtraction can underflow and let an out-of-range buffer offset reach the data path. The invalid offset is used by three request paths. VIRTIO_BLK_T_OUT copies guest data to blk->buffer + offset through vringh_iov_pull_iotlb(), causing an out-of-bounds write in _copy_from_iter() or memcpy(). VIRTIO_BLK_T_IN copies from blk->buffer + offset to the guest through vringh_iov_push_iotlb(), causing an out-of-bounds read in _copy_to_iter(). VIRTIO_BLK_T_WRITE_ZEROES passes blk->buffer + offset to memset(), causing an out-of-bounds write. Reject starts at or beyond the capacity before the subtraction. Treat the capacity boundary as invalid because the IN and OUT paths round byte counts down to sectors for validation but later copy the original byte counts. A sub-sector request at the capacity boundary would otherwise still access past the end of the buffer. I found this bug myself, though the patch was written with AI assistance.

View the official NVD record for CVE-2026-97991

CVE data is sourced from NVD/CNA records and optional enrichment. Validate against the vendor advisory before taking production action.