{"id":"CVE-2026-99019","kind":"vulnerability","aliases":["CVE-2026-99019"],"related":[],"title":"Linux kernel: SCSI changer driver leaks device references, blocking module unload","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nscsi: ch: Do not keep references to data transfer element devices\n\nch_readconfig() looks up the scsi_device of every data transfer element\nwhose SCSI id the changer reports in READ ELEMENT STATUS, and stores it in\nch->dt[]. scsi_device_lookup() takes a reference, and nothing ever drops\nit: ch_destroy() frees the array with kfree(). ch->dt[] is read nowhere\nelse - it only supplies the vendor, model and revision printed in the same\nloop.\n\nOnce such a drive is removed, its scsi_device can never be released. It\nstays on the host's device list at its address, so a new device there is\nrefused by anything that walks the list - target_core_pscsi reports\n\"scsi_device_get() failed for H:C:T:L\" - and the low-level driver's module\ncan no longer be unloaded. Only a reboot recovers.\n\nIt shows with any changer that reports its drives' ids; with the mhvtl\nvirtual library (IBM 3573-TL personality), each create and remove of a\nlibrary with four drives leaves four references behind, counted by the\nmodule's use count in lsmod. With ch not bound the count is unchanged, and\nwith this patch applied it is unchanged too.\n\nDrop the reference as soon as the name has been printed, and remove the now\nunused dt[] array. That also removes the array leaked when ch_probe() fails\nafter ch_readconfig().\n\nThe same leak was reported with an RFC patch in 2022, which was not merged.","summary":"The Linux SCSI media changer driver (ch) takes a reference to each data transfer element drive it reads and never releases it, so removed drives stay pinned on the host. The result is a resource leak that can block device reuse and module unload until reboot, and the sources do not describe an attacker gaining access.","severity":"unknown","cvss":null,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["infrastructure","kernel","linux","scsi","self-hosted","tape-library"],"not_affected_if":["ch-module-not-loaded","no-scsi-changer"],"how_to_check":"- Run `lsmod | grep ch` and compare the use count before and after attaching and removing a SCSI changer with its drives, if the `ch` module is loaded.\n- Check whether the `ch` module is loaded at all with `lsmod | grep '^ch '`; systems without a SCSI media changer are not exposed in practice.\n- Check the running kernel with `uname -r` and compare it against the fixed kernel version in the upstream stable branch.","fix":"- Update to a kernel release that includes the upstream commit 'scsi: ch: Do not keep references to data transfer element devices'; the sources do not name the exact version, so unknown.\n- Until patched, avoid repeatedly adding and removing SCSI changer libraries on the same host, and reboot after a removal if a drive will not reattach.","status":"open","published_at":"2026-10-23T13:17:24+00:00","first_seen_at":"2026-10-23T21:57:33+00:00","triaged_at":"2026-10-25T04:55:41+00:00","updated_at":"2026-10-25T04:55:41+00:00","category":"infrastructure","confidence":0.6,"triage":{"at":"2026-10-25T04:55:41Z","model":"claude-haiku-5-5","output":{"fix":"- Update to a kernel release that includes the upstream commit 'scsi: ch: Do not keep references to data transfer element devices'; the sources do not name the exact version, so unknown.\n- Until patched, avoid repeatedly adding and removing SCSI changer libraries on the same host, and reboot after a removal if a drive will not reattach.","reach":"local","title":"Linux kernel: SCSI changer driver leaks device references, blocking module unload","impact":"low","summary":"The Linux SCSI media changer driver (ch) takes a reference to each data transfer element drive it reads and never releases it, so removed drives stay pinned on the host. The result is a resource leak that can block device reuse and module unload until reboot, and the sources do not describe an attacker gaining access.","category":"infrastructure","nicknames":[],"who_cares":["linux","kernel","scsi","tape-library","self-hosted"],"confidence":0.6,"needs_auth":"unknown","worst_case":"Leaked device references block driver unload and device reuse until reboot.","analyst_note":"Sources give only the NVD entry and kernel commit text; check the upstream kernel stable advisories for the fixed version and any CVSS score.","how_to_check":"- Run `lsmod | grep ch` and compare the use count before and after attaching and removing a SCSI changer with its drives, if the `ch` module is loaded.\n- Check whether the `ch` module is loaded at all with `lsmod | grep '^ch '`; systems without a SCSI media changer are not exposed in practice.\n- Check the running kernel with `uname -r` and compare it against the fixed kernel version in the upstream stable branch.","needs_analyst":true,"not_affected_if":["no-scsi-changer","ch-module-not-loaded"],"who_is_affected":"Hosts that use a SCSI media changer (tape library or virtual library such as mhvtl) with the Linux `ch` driver loaded and the changer reporting its drives' SCSI ids. The leak occurs on each create and remove of such a library, so systems that repeatedly hot-swap changer drives are the ones that feel it. Systems without SCSI changers can skip it.","user_interaction":"no","needs_special_setup":"yes","severity_if_unknown":"unknown"},"cost_usd":0.000759,"input_tokens":3714,"output_tokens":775,"severity_before":"unknown"},"analyst_status":null,"analyst_note":null,"search":"'-2026':13A,16A '-99019':14A,17A '2022':337C '3573':253C 'access':83B 'address':193C 'also':315C 'anyth':202C 'appli':291C 'array':148C,313C,318C 'attack':81B 'behind':269C 'block':9A,66B 'bound':282C 'c':217C 'ch':34B,95C,105C,131C,144C,151C,280C,321C,325C 'changer':4A,32B,121C,241C 'core':208C 'count':270C,276C,284C 'creat':257C 'cve':12A,15A 'data':40B,101C,114C 'describ':79B 'destroy':145C 'devic':7A,67B,104C,111C,134C,178C,189C,197C,212C 'drive':43B,52B,173C,245C,265C 'driver':5A,33B,225C 'drop':142C,296C 'dt':132C,152C,312C 'element':42B,103C,116C,125C 'els':156C 'ever':141C 'everi':113C 'fail':214C,323C 'follow':89C 'four':264C,267C 'free':146C 'gain':82B 'get':213C 'h':216C 'host':24B,57B,187C 'ibm':252C 'id':119C,246C 'infrastructur':18B 'keep':98C 'kernel':2A,19B,87C 'kfree':150C 'l':219C 'leak':6A,63B,319C,329C 'leav':266C 'level':224C 'librari':27B,251C,262C 'linux':1A,20B,29B,86C 'list':190C,206C 'longer':230C 'look':107C 'lookup':135C 'loop':169C 'low':223C 'low-level':222C 'lsmod':278C 'media':31B 'merg':341C 'mhvtl':249C 'model':162C 'modul':10A,70B,227C,273C 'name':303C 'never':47B,180C 'new':196C 'noth':140C 'nowher':155C 'patch':290C,335C 'person':255C 'pin':54B 'print':165C,306C 'probe':322C 'pscsi':209C 'read':45B,124C,154C 'readconfig':106C,326C 'reboot':73B,235C 'recov':236C 'refer':8A,37B,99C,138C,268C,298C 'refus':200C 'releas':48B,182C 'remov':51B,175C,259C,308C,316C 'report':122C,210C,243C,331C 'resolv':93C 'resourc':62B 'result':59B 'reus':68B 'revis':164C 'rfc':334C 'scsi':3A,21B,30B,94C,110C,118C,133C,177C,211C 'self':23B 'self-host':22B 'show':238C 'soon':300C 'sourc':76B 'status':126C 'stay':53B,184C 'store':128C 'suppli':159C 'take':35B,136C 'tape':26B 'tape-librari':25B 'target':207C 'tl':254C 'transfer':41B,102C,115C 'unchang':286C,294C 'unload':11A,71B,232C 'unus':311C 'use':275C 'vendor':161C 'virtual':250C 'vulner':90C 'walk':204C 'whose':117C","nicknames":[],"mitigations":[],"who_affected":"Hosts that use a SCSI media changer (tape library or virtual library such as mhvtl) with the Linux `ch` driver loaded and the changer reporting its drives' SCSI ids. The leak occurs on each create and remove of such a library, so systems that repeatedly hot-swap changer drives are the ones that feel it. Systems without SCSI changers can skip it.","tier":"C","verified":{},"analyst_revisit_at":null,"first_public_at":"2026-10-23T13:17:24+00:00","kev":null,"cvss_vector":null,"cvss_by":null,"poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-99019","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-99019","severity":null,"published_at":"2026-10-23T13:17:24+00:00","modified_at":"2026-10-23T13:17:24+00:00","first_seen_at":"2026-10-23T21:57:33+00:00","fetched_at":"2026-10-23T22:29:03+00:00","note":null}],"documents":[],"notice":"Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai"}