OCTOBER 9, 2026
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Case File

CVE-2026-97991

HIGH · CVSS 7.8 EPSS 0.12%

Source: NVD + CISA KEV + EPSS · Published 2026-09-25 · Last synced 2026-10-09

CyberRota Analysis

AI-Generated

The vulnerability affects the Linux kernel's vdpa_sim_blk component, where improper validation of sector start requests can lead to out-of-bounds memory access. This can result in potential data corruption or unauthorized access due to out-of-bounds reads and writes during block operations. Organizations utilizing Linux systems with virtualized environments should prioritize addressing this issue to mitigate risks associated with data integrity and security.

CVE
CVE-2026-97991
Severity
HIGH
CVSS
7.8
EPSS
0.12%
Linux

Original NVD Description

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.