{"cve":"CVE-2026-98773","nvd":{"published":"2026-10-18T16:17:31.223","modified":"2026-10-21T13:21:45.547","status":"Received","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nUSB: cdc-acm: skip URB restart in port_shutdown if disconnected\n\nacm_port_shutdown() is called from the tty-port machinery whenever the\nlast user closes the port.  acm_disconnect() sets acm->disconnected and\ncalls tty_port_tty_vhangup(), which eventually triggers port_shutdown().\nAt that point acm_disconnect() has already called acm_poison_urbs() and\nis about to free the control and read URBs.\n\nHowever, acm_port_shutdown() unconditionally calls acm_unpoison_urbs()\nand, when the ALWAYS_POLL_CTRL quirk is set, immediately re-submits the\nctrlurb and all read URBs.  If the concurrent acm_disconnect() then\nfrees those URBs and their DMA buffers while they are in-flight, the\nresult is a use-after-free in acm_ctrl_irq() or acm_read_bulk_callback()\naccessing the freed DMA memory.\n\nFix by checking acm->disconnected after draining the delayed anchor and\nreturning early: if we are in a disconnect path the URBs must remain\npoisoned and must not be resubmitted.\n\nThe early return is placed after the delayed-anchor drain loop because\nthat loop only cancels write-side accounting (wb->use = false and\nautopm counter) and does not touch the hardware path.","cvss_v4":null,"cvss_v3":null,"cwes":[],"references":["https://git.kernel.org/stable/c/420ca35af891d33522cc08504768ccd60a4c450a","https://git.kernel.org/stable/c/9742905d9ed5bf23ebe4c100dec80b6bc50fb522","https://git.kernel.org/stable/c/a0ed07b5bbb2d8fcef86810453216070691816e7","https://git.kernel.org/stable/c/d86775e79838d7d2e38ccf506a7d0f8e2dd4d5d0","https://git.kernel.org/stable/c/dc614d6bc991740d41d5a99ac7765c4b675dda88"],"products":[],"source":"nvd","synced_at":"2026-10-22T16:41:11.231219466+00:00"},"epss":{"cve":"CVE-2026-98773","score":0.00168,"percentile":0.05975,"date":"2026-10-25"},"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."]}