{"id":"CVE-2026-89894","title":"In the Linux kernel, the following vulnerability has been resolved:\n\nmedia: cx231xx: reject geometry changes while the VBI queue is busy\n\nvidioc_s_fmt_vid_cap() and vidioc_s_std() change the device-wide\ndev->width / dev->norm but only re…","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nmedia: cx231xx: reject geometry changes while the VBI queue is busy\n\nvidioc_s_fmt_vid_cap() and vidioc_s_std() change the device-wide\ndev->width / dev->norm but only re…","severity":"high","cvss":7.8,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","vendor":"Linux","product":"Linux","affected":["Linux >= 7c617138b8254a6bb60bfb5b8fc53eb8b3d6c3ab < aa3314506deb9703bcf0e889db08959440228fbf","Linux >= 7c617138b8254a6bb60bfb5b8fc53eb8b3d6c3ab < 90d50648af36a1fbf5dbc99238de6fd0e58a13e0","Linux >= 7c617138b8254a6bb60bfb5b8fc53eb8b3d6c3ab < a5dd3d7fba358ff9486f3f51b2a9038348c0970a","Linux >= 7c617138b8254a6bb60bfb5b8fc53eb8b3d6c3ab < 54ac6df8b8d97eddc3ae97fd2045bdedc8541b6d","Linux >= 7c617138b8254a6bb60bfb5b8fc53eb8b3d6c3ab < 1d1079db8d1807e259a1d2679ed314949797aad9","Linux >= 7c617138b8254a6bb60bfb5b8fc53eb8b3d6c3ab < 7087bef6510c7df5df0b19192633b8ecc0f33a6f","Linux >= 7c617138b8254a6bb60bfb5b8fc53eb8b3d6c3ab < a636c72c7f522d984fa498fc0631f33a2d0be3fd","Linux >= 7c617138b8254a6bb60bfb5b8fc53eb8b3d6c3ab < 627a121c15fe05a541f44d86016294b80bada75d","Linux 5.5"],"published":"2026-09-16","updated":"2026-09-16","sourceUpdated":"2026-09-16T15:18:15.790","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-89894","references":[{"url":"https://git.kernel.org/stable/c/1d1079db8d1807e259a1d2679ed314949797aad9","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/54ac6df8b8d97eddc3ae97fd2045bdedc8541b6d","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/627a121c15fe05a541f44d86016294b80bada75d","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/7087bef6510c7df5df0b19192633b8ecc0f33a6f","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/90d50648af36a1fbf5dbc99238de6fd0e58a13e0","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/a5dd3d7fba358ff9486f3f51b2a9038348c0970a","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/a636c72c7f522d984fa498fc0631f33a2d0be3fd","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/aa3314506deb9703bcf0e889db08959440228fbf","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"}],"tags":["nvd","cve.org"],"ingestedAt":"2026-09-16T10:53:53.981Z","epss":0.00164,"epssPercentile":0.0602,"slug":"CVE-2026-89894","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nmedia: cx231xx: reject geometry changes while the VBI queue is busy\n\nvidioc_s_fmt_vid_cap() and vidioc_s_std() change the device-wide\ndev->width / dev->norm but only refuse the change when the *video* queue\n(dev->vidq) is busy. The VBI queue (dev->vbiq) shares that same geometry:\ncx231xx_init_vbi_isoc() latches dma_q->lines_per_field from dev->norm,\nthe VBI videobuf2 plane is sized from dev->width / dev->norm in\nvbi_queue_setup() and vbi_buf_prepare(), and cx231xx_do_vbi_copy() then\nrecomputes the destination offset from the *live* dev->width and the\nlatched lines_per_field on every URB completion:\n\n\toffset = lines_completed * (dev->width << 1) + ...;\n\tif (dma_q->current_field == 2)\n\t\toffset += dev->width * 2 * dma_q->lines_per_field;\n\tmemcpy(plane + offset, p_buffer, lencopy);\n\nBecause the VBI node shares video_ioctl_ops with the video node, an\napplication can size a small VBI plane (REQBUFS/QBUF with a small width,\nor with the NTSC standard), then enlarge dev->width (or switch dev->norm\nto PAL) through the video node while the VBI stream is running -- the\nchange is allowed because only dev->vidq is checked -- and let the device\ndeliver a field-2 VBI payload. cx231xx_do_vbi_copy() now computes the\noffset with the larger geometry and memcpy()s past the end of the smaller\nplane that was already allocated, a heap out-of-bounds write whose offset\nis attacker-chosen and whose contents come from the device. The\nper-field guard in cx231xx_copy_vbi_line() does not help: it bounds the\ncopy against the latched lines_per_field, not the plane's real capacity,\nand vb2 does not re-run buf_prepare() for an already prepared buffer.\n\nRefuse the format/standard change when the VBI queue is busy as well, so\nthe geometry cannot change underneath an allocated VBI buffer.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"twilight","depthScore":43,"depthScoreParts":{"impact":42.9,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[{"seq":205172,"id":"CVE-2026-89894","ts":1789570705577,"field":"cvss","old":null,"new":"7.8"},{"seq":205171,"id":"CVE-2026-89894","ts":1789570705577,"field":"severity","old":"none","new":"high"}]}