{"id":"CVE-2026-98773","state":"PUBLISHED","title":"USB: cdc-acm: skip URB restart in port_shutdown if disconnected","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.","publishedAt":"2026-10-18T15:48:09.093Z","updatedAt":"2026-10-30T12:39:41.890Z","severity":null,"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"d826061aa64cb28089bf4c73e301dd7928662b84","status":"affected","lessThan":"d97da42e9de577dc827d4e8866e6971deefe2d9c","versionType":"git"},{"version":"8fb82e3555a7d56a05d8ef0edee9859f889c0860","status":"affected","lessThan":"d86775e79838d7d2e38ccf506a7d0f8e2dd4d5d0","versionType":"git"},{"version":"603d5a7110832e10165d21f9a1486399457177de","status":"affected","lessThan":"9742905d9ed5bf23ebe4c100dec80b6bc50fb522","versionType":"git"},{"version":"5d29d7ff8679e5a525f22da467ba33c042e8029b","status":"affected","lessThan":"a0ed07b5bbb2d8fcef86810453216070691816e7","versionType":"git"},{"version":"f58752ebcb35e156c85cd1a82d6579c7af3b9023","status":"affected","lessThan":"420ca35af891d33522cc08504768ccd60a4c450a","versionType":"git"},{"version":"f58752ebcb35e156c85cd1a82d6579c7af3b9023","status":"affected","lessThan":"dc614d6bc991740d41d5a99ac7765c4b675dda88","versionType":"git"},{"version":"283f8162cc3c82086537cbc7dc01870dbeb07a91","status":"affected","versionType":"git"},{"version":"f77f10bc76c2da86b4248269472f6d971e37828b","status":"affected","versionType":"git"},{"version":"6.1.175","status":"affected","lessThan":"6.1.191","versionType":"semver"},{"version":"6.6.136","status":"affected","lessThan":"6.6.160","versionType":"semver"},{"version":"6.12.83","status":"affected","lessThan":"6.12.113","versionType":"semver"},{"version":"6.18.24","status":"affected","lessThan":"6.18.56","versionType":"semver"},{"version":"6.19.14","status":"affected","lessThan":"6.20","versionType":"semver"},{"version":"7.0.1","status":"affected","lessThan":"7.1","versionType":"semver"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/usb/class/cdc-acm.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"7.1","status":"affected"},{"version":"0","status":"unaffected","lessThan":"7.1","versionType":"semver"},{"version":"6.1.191","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.160","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.113","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.56","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.10","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/usb/class/cdc-acm.c"]}],"references":["https://git.kernel.org/stable/c/d97da42e9de577dc827d4e8866e6971deefe2d9c","https://git.kernel.org/stable/c/d86775e79838d7d2e38ccf506a7d0f8e2dd4d5d0","https://git.kernel.org/stable/c/9742905d9ed5bf23ebe4c100dec80b6bc50fb522","https://git.kernel.org/stable/c/a0ed07b5bbb2d8fcef86810453216070691816e7","https://git.kernel.org/stable/c/420ca35af891d33522cc08504768ccd60a4c450a","https://git.kernel.org/stable/c/dc614d6bc991740d41d5a99ac7765c4b675dda88"],"weaknesses":[],"ingestedAt":"2026-10-30T13:00:06.648Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/98xxx/CVE-2026-98773.json","commit":"cb14bf1b43b0c9f05f7f40eae2246263fd430780","baselineCommit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-98773","state":"PUBLISHED","datePublished":"2026-10-18T15:48:09.093Z","dateUpdated":"2026-10-30T12:39:41.890Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-09-25T10:25:14.369Z"},"containers":{"cna":{"title":"USB: cdc-acm: skip URB restart in port_shutdown if disconnected","descriptions":[{"lang":"en","value":"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."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"d826061aa64cb28089bf4c73e301dd7928662b84","status":"affected","lessThan":"d97da42e9de577dc827d4e8866e6971deefe2d9c","versionType":"git"},{"version":"8fb82e3555a7d56a05d8ef0edee9859f889c0860","status":"affected","lessThan":"d86775e79838d7d2e38ccf506a7d0f8e2dd4d5d0","versionType":"git"},{"version":"603d5a7110832e10165d21f9a1486399457177de","status":"affected","lessThan":"9742905d9ed5bf23ebe4c100dec80b6bc50fb522","versionType":"git"},{"version":"5d29d7ff8679e5a525f22da467ba33c042e8029b","status":"affected","lessThan":"a0ed07b5bbb2d8fcef86810453216070691816e7","versionType":"git"},{"version":"f58752ebcb35e156c85cd1a82d6579c7af3b9023","status":"affected","lessThan":"420ca35af891d33522cc08504768ccd60a4c450a","versionType":"git"},{"version":"f58752ebcb35e156c85cd1a82d6579c7af3b9023","status":"affected","lessThan":"dc614d6bc991740d41d5a99ac7765c4b675dda88","versionType":"git"},{"version":"283f8162cc3c82086537cbc7dc01870dbeb07a91","status":"affected","versionType":"git"},{"version":"f77f10bc76c2da86b4248269472f6d971e37828b","status":"affected","versionType":"git"},{"version":"6.1.175","status":"affected","lessThan":"6.1.191","versionType":"semver"},{"version":"6.6.136","status":"affected","lessThan":"6.6.160","versionType":"semver"},{"version":"6.12.83","status":"affected","lessThan":"6.12.113","versionType":"semver"},{"version":"6.18.24","status":"affected","lessThan":"6.18.56","versionType":"semver"},{"version":"6.19.14","status":"affected","lessThan":"6.20","versionType":"semver"},{"version":"7.0.1","status":"affected","lessThan":"7.1","versionType":"semver"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/usb/class/cdc-acm.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"7.1","status":"affected"},{"version":"0","status":"unaffected","lessThan":"7.1","versionType":"semver"},{"version":"6.1.191","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.160","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.113","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.56","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.10","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/usb/class/cdc-acm.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/d97da42e9de577dc827d4e8866e6971deefe2d9c"},{"url":"https://git.kernel.org/stable/c/d86775e79838d7d2e38ccf506a7d0f8e2dd4d5d0"},{"url":"https://git.kernel.org/stable/c/9742905d9ed5bf23ebe4c100dec80b6bc50fb522"},{"url":"https://git.kernel.org/stable/c/a0ed07b5bbb2d8fcef86810453216070691816e7"},{"url":"https://git.kernel.org/stable/c/420ca35af891d33522cc08504768ccd60a4c450a"},{"url":"https://git.kernel.org/stable/c/dc614d6bc991740d41d5a99ac7765c4b675dda88"}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-10-30T12:39:41.890Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.1.175","versionEndExcluding":"6.1.191"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.6.136","versionEndExcluding":"6.6.160"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.12.83","versionEndExcluding":"6.12.113"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.18.24","versionEndExcluding":"6.18.56"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"7.1","versionEndExcluding":"7.2.10"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"7.1","versionEndExcluding":"7.3"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.19.14"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"7.0.1"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}