{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-89894", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-09-11T19:38:34.773Z", "datePublished": "2026-09-16T10:31:56.101Z", "dateUpdated": "2026-10-19T08:54:27.208Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-19T08:54:27.208Z" }, "descriptions": [ { "lang": "en", "value": "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 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." } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "baseScore": 7.8, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "value": "AV:L - The overflow is reached only through local V4L2 ioctls (VIDIOC_S_FMT/VIDIOC_S_STD plus REQBUFS/QBUF/STREAMON) on the cx231xx /dev/videoN and /dev/vbiN nodes. A USB capture stick being present is a hardware precondition; the attacker does not inject USB packets, so the path is Local rather than Physical.\nAC:L - The attacker fully controls the sequence: shrink width via VIDIOC_S_FMT, allocate a small VBI plane, STREAMON, then enlarge width or switch standard on the video node while only vidq was checked. Subsequent URB completions copy field-2 VBI with the new geometry into the old plane with no race or layout outside the attacker's control.\nPR:L - cx231xx_v4l2_open(), vidioc_s_fmt_vid_cap(), and vidioc_s_std() perform no capability checks. Triggering the bug needs only an unprivileged local user who can open the V4L2 nodes, which udev grants via the video group and uaccess/logind (or the Android camera context), not init-namespace root.\nUI:N - The attacking process opens /dev/videoN and /dev/vbiN and issues the ioctl sequence itself. No separate victim action such as plugging in a device, mounting a filesystem, or running a privileged helper is required.\nS:U - The out-of-bounds memcpy corrupts kernel vmalloc memory belonging to the same host kernel. Impact is local privilege-escalation or denial of service within one security authority, not a VM escape, IOMMU bypass, or other cross-boundary effect.\nC:H - cx231xx_do_vbi_copy() memcpy()s past the undersized VBI plane at an attacker-chosen offset derived from the new width and latched lines_per_field. That heap out-of-bounds write can smash adjacent vmalloc objects and is leverageable for a kernel read primitive.\nI:H - The same attacker-chosen-offset heap out-of-bounds write overwrites kernel memory after the VBI buffer on every field-2 URB completion. An out-of-bounds write of this form is sufficient for control-flow hijacking and an arbitrary write primitive.\nA:H - memcpy() past the allocated VBI plane faults on a vmalloc guard page or corrupts adjacent kernel memory, producing a kernel oops or panic from URB completion context and taking down the host." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "drivers/media/usb/cx231xx/cx231xx-video.c" ], "versions": [ { "version": "7c617138b8254a6bb60bfb5b8fc53eb8b3d6c3ab", "lessThan": "aa3314506deb9703bcf0e889db08959440228fbf", "status": "affected", "versionType": "git" }, { "version": "7c617138b8254a6bb60bfb5b8fc53eb8b3d6c3ab", "lessThan": "90d50648af36a1fbf5dbc99238de6fd0e58a13e0", "status": "affected", "versionType": "git" }, { "version": "7c617138b8254a6bb60bfb5b8fc53eb8b3d6c3ab", "lessThan": "a5dd3d7fba358ff9486f3f51b2a9038348c0970a", "status": "affected", "versionType": "git" }, { "version": "7c617138b8254a6bb60bfb5b8fc53eb8b3d6c3ab", "lessThan": "54ac6df8b8d97eddc3ae97fd2045bdedc8541b6d", "status": "affected", "versionType": "git" }, { "version": "7c617138b8254a6bb60bfb5b8fc53eb8b3d6c3ab", "lessThan": "1d1079db8d1807e259a1d2679ed314949797aad9", "status": "affected", "versionType": "git" }, { "version": "7c617138b8254a6bb60bfb5b8fc53eb8b3d6c3ab", "lessThan": "7087bef6510c7df5df0b19192633b8ecc0f33a6f", "status": "affected", "versionType": "git" }, { "version": "7c617138b8254a6bb60bfb5b8fc53eb8b3d6c3ab", "lessThan": "a636c72c7f522d984fa498fc0631f33a2d0be3fd", "status": "affected", "versionType": "git" }, { "version": "7c617138b8254a6bb60bfb5b8fc53eb8b3d6c3ab", "lessThan": "627a121c15fe05a541f44d86016294b80bada75d", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "drivers/media/usb/cx231xx/cx231xx-video.c" ], "versions": [ { "version": "5.5", "status": "affected" }, { "version": "0", "lessThan": "5.5", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.270", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.221", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.188", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.157", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.110", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.51", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.2.5", "lessThanOrEqual": "7.2.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.3", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix" } ] } ], "cpeApplicability": [ { "nodes": [ { "operator": "OR", "negate": false, "cpeMatch": [ { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.5", "versionEndExcluding": "5.10.270" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.5", "versionEndExcluding": "5.15.221" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.5", "versionEndExcluding": "6.1.188" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.5", "versionEndExcluding": "6.6.157" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.5", "versionEndExcluding": "6.12.110" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.5", "versionEndExcluding": "6.18.51" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.5", "versionEndExcluding": "7.2.5" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.5", "versionEndExcluding": "7.3" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/aa3314506deb9703bcf0e889db08959440228fbf" }, { "url": "https://git.kernel.org/stable/c/90d50648af36a1fbf5dbc99238de6fd0e58a13e0" }, { "url": "https://git.kernel.org/stable/c/a5dd3d7fba358ff9486f3f51b2a9038348c0970a" }, { "url": "https://git.kernel.org/stable/c/54ac6df8b8d97eddc3ae97fd2045bdedc8541b6d" }, { "url": "https://git.kernel.org/stable/c/1d1079db8d1807e259a1d2679ed314949797aad9" }, { "url": "https://git.kernel.org/stable/c/7087bef6510c7df5df0b19192633b8ecc0f33a6f" }, { "url": "https://git.kernel.org/stable/c/a636c72c7f522d984fa498fc0631f33a2d0be3fd" }, { "url": "https://git.kernel.org/stable/c/627a121c15fe05a541f44d86016294b80bada75d" } ], "title": "media: cx231xx: reject geometry changes while the VBI queue is busy", "x_generator": { "engine": "bippy-1.2.0" } } } }