{"schema_version":"1.9.0","id":"CVE-2026-63929","published":"2026-07-19T14:55:29.309Z","modified":"2026-08-27T18:26:12.879834523Z","related":["SUSE-SU-2026:23066-1","SUSE-SU-2026:23068-1","SUSE-SU-2026:23221-1","SUSE-SU-2026:23231-1","SUSE-SU-2026:23237-1","openSUSE-SU-2026:21555-1"],"summary":"iio: buffer: Fix DMA fence leak in iio_buffer_enqueue_dmabuf()","details":"In the Linux kernel, the following vulnerability has been resolved:\n\niio: buffer: Fix DMA fence leak in iio_buffer_enqueue_dmabuf()\n\niio_buffer_enqueue_dmabuf() allocates a struct iio_dma_fence (104 bytes,\nkmalloc-128) via kmalloc_obj()+dma_fence_init(), which sets the initial\nkref to 1.  It then calls dma_resv_add_fence() which takes a second\nreference (kref=2), and stores a raw pointer in block->fence.\n\nOn the success path the function returns without calling dma_fence_put()\nto release the initial reference, so every buffer enqueue permanently\nleaks one kmalloc-128 allocation.\n\nThe iio_buffer_cleanup() work item only releases the temporary reference\ntaken during completion signalling by iio_buffer_signal_dmabuf_done();\nthe initial reference from dma_fence_init() is never released.\n\nWith four iio_rwdev instances at 240kHz and 512 samples per buffer,\nthis produces ~1875 kmalloc-128 allocations per second matching the\nobserved slab growth exactly. A test with ftrace confirmed that the\ndma_fence_destroy event was never triggered.\n\nFix by calling dma_fence_put() after dma_resv_add_fence(), transferring\nownership of the fence to the DMA reservation object. The DMA fence then\ngets properly discarded after being signalled.","affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"3e26d9f08fbe0b73e951a5e810fdb7a332b7e37f"},{"fixed":"9678aeed8b77d495a417dd057d479f3733094019"},{"fixed":"3412a95afaa5d3262008dfc34f3c7be33d8151dc"},{"fixed":"96cdeaba6a008503455b78a9641c05c2a886a7ec"},{"fixed":"a093999355084bdbfe6e97f1dd232e58a1525f0b"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-63929.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"6.11.0"},{"fixed":"6.12.93"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.18.35"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"7.0.12"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-63929.json"}}],"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/3412a95afaa5d3262008dfc34f3c7be33d8151dc"},{"type":"WEB","url":"https://git.kernel.org/stable/c/9678aeed8b77d495a417dd057d479f3733094019"},{"type":"WEB","url":"https://git.kernel.org/stable/c/96cdeaba6a008503455b78a9641c05c2a886a7ec"},{"type":"WEB","url":"https://git.kernel.org/stable/c/a093999355084bdbfe6e97f1dd232e58a1525f0b"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/63xxx/CVE-2026-63929.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-63929"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/63xxx/CVE-2026-63929.json"}}