{"id":"CVE-2026-89881","summary":"media: rtl2832_sdr: use vb2_video_unregister_device() on remove to fix DMA leak","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nmedia: rtl2832_sdr: use vb2_video_unregister_device() on remove to fix DMA leak\n\nrtl2832_sdr_remove() runs on USB disconnect and clears dev-\u003eudev to\nNULL before any pending streaming teardown has run. When user space\nlater closes its file descriptor, vb2 calls rtl2832_sdr_stop_streaming()\nwhich in turn calls rtl2832_sdr_free_stream_bufs(). That helper releases\neach coherent buffer with:\n\n    usb_free_coherent(dev-\u003eudev, dev-\u003ebuf_size,\n                      dev-\u003ebuf_list[dev-\u003ebuf_num],\n                      dev-\u003edma_addr[dev-\u003ebuf_num]);\n\nusb_free_coherent() returns immediately when its dev argument is NULL,\nso every DMA stream buffer that was live at disconnect is silently\nleaked. The URBs allocated in rtl2832_sdr_alloc_urbs() outlive the\ndevice for the same reason.\n\nThe rtl2832_sdr driver uses vb2_fop_release() in its file_operations,\nso replace video_unregister_device(&dev-\u003evdev) with\nvb2_video_unregister_device(&dev-\u003evdev) and move it before clearing\ndev-\u003eudev. vb2_video_unregister_device() releases the vb2 queue, which\nsynchronously runs rtl2832_sdr_stop_streaming() if streaming is active,\nso URBs and coherent DMA stream buffers are freed while dev-\u003eudev is\nstill valid.\n\nvb2_video_unregister_device() locks vdev-\u003equeue-\u003elock (vb_queue_lock)\ninternally, and stop_streaming() locks v4l2_lock, so the previous outer\nmutex_lock(&dev-\u003evb_queue_lock) / mutex_lock(&dev-\u003ev4l2_lock) pair\naround the unregister sequence would self-deadlock and has been removed.\nA short v4l2_lock critical section around dev-\u003eudev = NULL remains so\nany ioctl path that still holds the file descriptor sees coherent state.\n\nIssue identified by automated review of the INV-003 series at\nhttps://sashiko.dev/","modified":"2026-09-18T03:48:33.720740246Z","published":"2026-09-16T10:31:46.966Z","database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/89xxx/CVE-2026-89881.json"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/034b6a4f9589c04bc3f2bd5125658cd72d3e17c8"},{"type":"WEB","url":"https://git.kernel.org/stable/c/053581d4657c6b5289c5de71a4828d313c005189"},{"type":"WEB","url":"https://git.kernel.org/stable/c/0ef9f19010ae4ba93aca211ea8f0081b9bf7aab2"},{"type":"WEB","url":"https://git.kernel.org/stable/c/234c46b95a032232e31fa5987b84fb8f87a9693b"},{"type":"WEB","url":"https://git.kernel.org/stable/c/7443b16b6dd8889a3b9c5236a09e7c58f0d11dae"},{"type":"WEB","url":"https://git.kernel.org/stable/c/a0d9d9a3b41a1346c26af57aade6ba3f552fa171"},{"type":"WEB","url":"https://git.kernel.org/stable/c/bbf15e83c37d9ac938b7c35c02b748fe54230010"},{"type":"WEB","url":"https://git.kernel.org/stable/c/dabb047c62668f280998e29117c55e41aabac336"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/89xxx/CVE-2026-89881.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-89881"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"771138920eafa399f68d3492c8a75dfeea23474b"},{"fixed":"234c46b95a032232e31fa5987b84fb8f87a9693b"},{"fixed":"034b6a4f9589c04bc3f2bd5125658cd72d3e17c8"},{"fixed":"0ef9f19010ae4ba93aca211ea8f0081b9bf7aab2"},{"fixed":"053581d4657c6b5289c5de71a4828d313c005189"},{"fixed":"bbf15e83c37d9ac938b7c35c02b748fe54230010"},{"fixed":"7443b16b6dd8889a3b9c5236a09e7c58f0d11dae"},{"fixed":"a0d9d9a3b41a1346c26af57aade6ba3f552fa171"},{"fixed":"dabb047c62668f280998e29117c55e41aabac336"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-89881.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"3.15.0"},{"fixed":"5.10.270"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.11.0"},{"fixed":"5.15.221"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.16.0"},{"fixed":"6.1.188"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.2.0"},{"fixed":"6.6.157"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.7.0"},{"fixed":"6.12.110"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.18.51"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"7.2.5"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-89881.json"}}],"schema_version":"1.9.0"}