{"cve":"CVE-2026-53161","nvd":{"published":"2026-06-25T09:16:33.483","modified":"2026-07-06T16:42:02.893","status":"Analyzed","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nmisc: fastrpc: fix use-after-free of fastrpc_user in workqueue context\n\nThere is a race between fastrpc_device_release() and the workqueue\nthat processes DSP responses. When the user closes the file descriptor,\nfastrpc_device_release() frees the fastrpc_user structure. Concurrently,\nan in-flight DSP invocation can complete and fastrpc_rpmsg_callback()\nschedules context cleanup via schedule_work(&ctx->put_work). If the\nworkqueue runs fastrpc_context_free() in parallel with or after\nfastrpc_device_release() has freed the user structure, it dereferences\nthe freed fastrpc_user. Depending on the state of the context at the\ntime of the race, any one of the following accesses can be hit:\n\n 1. fastrpc_buf_free() calls fastrpc_ipa_to_dma_addr(buf->fl->cctx, ...)\n    to strip the SID bits from the stored IOVA before passing the\n    physical address to dma_free_coherent().\n\n 2. fastrpc_free_map() reads map->fl->cctx->vmperms[0].vmid to\n    reconstruct the source permission bitmask needed for the\n    qcom_scm_assign_mem() call that returns memory from the DSP VM\n    back to HLOS.\n\n 3. fastrpc_free_map() acquires map->fl->lock to safely remove the\n    map node from the fl->maps list.\n\nThe resulting use-after-free manifests as:\n\n  pc : fastrpc_buf_free+0x38/0x80 [fastrpc]\n  lr : fastrpc_context_free+0xa8/0x1b0 [fastrpc]\n  fastrpc_context_free+0xa8/0x1b0 [fastrpc]\n  fastrpc_context_put_wq+0x78/0xa0 [fastrpc]\n  process_one_work+0x180/0x450\n  worker_thread+0x26c/0x388\n\nAdd kref-based reference counting to fastrpc_user. Have each invoke\ncontext take a reference on the user at allocation time and release it\nwhen the context is freed. Release the initial reference in\nfastrpc_device_release() at file close. Move the teardown of the user\nstructure — freeing pending contexts, maps, mmaps, and the channel\ncontext reference — into the kref release callback fastrpc_user_free(),\nso that it runs only when the last reference is dropped, regardless of\nwhether that happens at device close or after the final in-flight\ncontext completes.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","score":7.8},"cwes":["CWE-416"],"references":["https://git.kernel.org/stable/c/5278ccd357e0d7aeeb1e76c0f3e0e02894a9897c","https://git.kernel.org/stable/c/c6e5c2be09f814377d7f1ce97370a5b7b3e02814","https://git.kernel.org/stable/c/d42679eef34dd590b694ce3b666c5e2ba10cd4bf","https://git.kernel.org/stable/c/df08fadcf0e5f3708365ec3b6d30b5aafd98bea1","https://git.kernel.org/stable/c/e1e3a05efe5954d5bad01157d79429d39a67a7ae"],"products":["linux:linux_kernel"],"source":"nvd","synced_at":"2026-10-19T22:41:17.107060303+00:00"},"epss":{"cve":"CVE-2026-53161","score":0.00126,"percentile":0.02227,"date":"2026-10-31"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}