{"api_version":"1","generated_at":"2026-09-16T16:13:30+00:00","cve":"CVE-2026-90044","urls":{"html":"https://cve.report/CVE-2026-90044","api":"https://cve.report/api/cve/CVE-2026-90044.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-90044","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-90044"},"summary":{"title":"usb: gadget: f_fs: Fix Use-After-Free in AIO error path","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nusb: gadget: f_fs: Fix Use-After-Free in AIO error path\n\nIn ffs_epfile_write_iter() and ffs_epfile_read_iter(), when ffs_epfile_io()\nfails with an error other than -EIOCBQUEUED, the io_data structure (`p`) is\nfreed. However, for AIO operations, the kiocb cancel function was already\narmed and kiocb->private was set to `p`.\n\nIf a concurrent cancel operation (such as sys_io_cancel()) executes after\nffs_epfile_io() fails but before the function frees `p`, a Use-After-Free\ncan occur when the cancellation handler accesses the freed pointer.\n\nTo securely fix this race condition, we must properly un-arm the\ncancellation. Invoking `kiocb->ki_complete()` does exactly this by\nacquiring `ctx->ctx_lock` and safely removing the kiocb from the active\nsequence. In doing so, it ensures that a parallel io_cancel can no longer\ndiscover the kiocb, effectively closing the race window.\n\nWe then return -EIOCBQUEUED to notify the VFS layer that the kiocb has been\nconsumed and it should avoid attempting to complete the request again or\ntriggering subsequent completion handlers.","state":"PUBLISHED","assigner":"Linux","published_at":"2026-09-16 11:17:17","updated_at":"2026-09-16 15:18:27"},"problem_types":[],"metrics":[{"version":"3.1","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","type":"Secondary","score":"7.8","severity":"HIGH","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","data":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","baseScore":7.8,"baseSeverity":"HIGH","attackVector":"LOCAL","attackComplexity":"LOW","privilegesRequired":"LOW","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"HIGH"}},{"version":"3.1","source":"CNA","type":"DECLARED","score":"7.8","severity":"HIGH","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","data":{"baseScore":7.8,"baseSeverity":"HIGH","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","version":"3.1"}}],"references":[{"url":"https://git.kernel.org/stable/c/4a2fb2d12b87b43724230abb52a1440617c7b6cc","name":"https://git.kernel.org/stable/c/4a2fb2d12b87b43724230abb52a1440617c7b6cc","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/153b5ecd29ed055562400bc17c91df3fd869b0ce","name":"https://git.kernel.org/stable/c/153b5ecd29ed055562400bc17c91df3fd869b0ce","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/e78dcb1f7ec271449c54984dc90c62a5ba272de7","name":"https://git.kernel.org/stable/c/e78dcb1f7ec271449c54984dc90c62a5ba272de7","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-90044","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-90044","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected de2080d41b5d584205e408d72021f0f335a046fc 153b5ecd29ed055562400bc17c91df3fd869b0ce git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected de2080d41b5d584205e408d72021f0f335a046fc 4a2fb2d12b87b43724230abb52a1440617c7b6cc git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected de2080d41b5d584205e408d72021f0f335a046fc e78dcb1f7ec271449c54984dc90c62a5ba272de7 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 4.0","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 4.0 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18.51 6.18.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.2.5 7.2.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.3-rc1 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":null,"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Linux","programFiles":["drivers/usb/gadget/function/f_fs.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"153b5ecd29ed055562400bc17c91df3fd869b0ce","status":"affected","version":"de2080d41b5d584205e408d72021f0f335a046fc","versionType":"git"},{"lessThan":"4a2fb2d12b87b43724230abb52a1440617c7b6cc","status":"affected","version":"de2080d41b5d584205e408d72021f0f335a046fc","versionType":"git"},{"lessThan":"e78dcb1f7ec271449c54984dc90c62a5ba272de7","status":"affected","version":"de2080d41b5d584205e408d72021f0f335a046fc","versionType":"git"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["drivers/usb/gadget/function/f_fs.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"4.0"},{"lessThan":"4.0","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"6.18.*","status":"unaffected","version":"6.18.51","versionType":"semver"},{"lessThanOrEqual":"7.2.*","status":"unaffected","version":"7.2.5","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"7.3-rc1","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.18.51","versionStartIncluding":"4.0","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.2.5","versionStartIncluding":"4.0","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.3-rc1","versionStartIncluding":"4.0","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nusb: gadget: f_fs: Fix Use-After-Free in AIO error path\n\nIn ffs_epfile_write_iter() and ffs_epfile_read_iter(), when ffs_epfile_io()\nfails with an error other than -EIOCBQUEUED, the io_data structure (`p`) is\nfreed. However, for AIO operations, the kiocb cancel function was already\narmed and kiocb->private was set to `p`.\n\nIf a concurrent cancel operation (such as sys_io_cancel()) executes after\nffs_epfile_io() fails but before the function frees `p`, a Use-After-Free\ncan occur when the cancellation handler accesses the freed pointer.\n\nTo securely fix this race condition, we must properly un-arm the\ncancellation. Invoking `kiocb->ki_complete()` does exactly this by\nacquiring `ctx->ctx_lock` and safely removing the kiocb from the active\nsequence. In doing so, it ensures that a parallel io_cancel can no longer\ndiscover the kiocb, effectively closing the race window.\n\nWe then return -EIOCBQUEUED to notify the VFS layer that the kiocb has been\nconsumed and it should avoid attempting to complete the request again or\ntriggering subsequent completion handlers."}],"metrics":[{"cvssV3_1":{"baseScore":7.8,"baseSeverity":"HIGH","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","version":"3.1"},"scenarios":[{"lang":"en","value":"AV:L - The UAF is in FunctionFS epfile AIO (`ffs_epfile_write_iter`/`read_iter` via `io_submit`/`io_cancel` on functionfs ep files), a local syscall path. `ffs_epfile_io()` can fail with `-EAGAIN` on `O_NONBLOCK` before any USB host is involved; this is the gadget userspace API, matching CVE-2024-36894/CVE-2026-63894 as Local rather than Physical.\nAC:L - The attacker controls both sides: one thread `io_submit`s AIO that fails after `kiocb_set_cancel_fn` (O_NONBLOCK `-EAGAIN`, halt, `-EFAULT`), while another calls `io_cancel`/`io_destroy`. The race between `kfree(p)` and `aio_remove_iocb` is freely retryable, so a race the attacker creates is AC:L.\nPR:L - FunctionFS mounts commonly use `uid=`/`gid=`/`fmode=` to delegate ep files to unprivileged gadget daemons (adbd/shell on Android, MTP, embedded USB services). Once mounted by init, those accounts can open ep files and issue AIO without init-namespace root.\nUI:N - The attacker performs `io_submit` and `io_cancel`/`io_destroy` on their own FunctionFS endpoint fds. No separate victim action is required beyond an already-deployed FunctionFS gadget.\nS:U - The use-after-free corrupts kernel heap (`ffs_io_data`) within the same host kernel security authority. This is ordinary local privilege escalation, not a VM escape or IOMMU/sandbox boundary cross.\nC:H - Use-after-free of `ffs_io_data`: `ffs_aio_cancel()` reads `kiocb->private` after `kfree`. Reclaim of that kmalloc object lets the attacker control `io_data->ep`/`req` and leak kernel memory via UDC dequeue; UAFs are scored High for confidentiality.\nI:H - A reclaimed `ffs_io_data` yields attacker-controlled pointers passed to `usb_ep_dequeue()` from `ffs_aio_cancel`, providing a heap write and control-flow hijack primitive. Kernel UAFs are scored High for integrity.\nA:H - Dereferencing the freed `ffs_io_data` in `ffs_aio_cancel` causes kernel oops/panic even without a full exploit; any such crash is High availability impact."}]}],"providerMetadata":{"dateUpdated":"2026-09-16T14:41:58.245Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/153b5ecd29ed055562400bc17c91df3fd869b0ce"},{"url":"https://git.kernel.org/stable/c/4a2fb2d12b87b43724230abb52a1440617c7b6cc"},{"url":"https://git.kernel.org/stable/c/e78dcb1f7ec271449c54984dc90c62a5ba272de7"}],"title":"usb: gadget: f_fs: Fix Use-After-Free in AIO error path","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-90044","datePublished":"2026-09-16T10:33:41.695Z","dateReserved":"2026-09-11T19:38:34.783Z","dateUpdated":"2026-09-16T14:41:58.245Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-09-16 11:17:17","lastModifiedDate":"2026-09-16 15:18:27","problem_types":[],"metrics":{"cvssMetricV31":[{"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","type":"Secondary","cvssData":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","baseScore":7.8,"baseSeverity":"HIGH","attackVector":"LOCAL","attackComplexity":"LOW","privilegesRequired":"LOW","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"HIGH"},"exploitabilityScore":1.8,"impactScore":5.9}]},"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"90044","Ordinal":"1","Title":"usb: gadget: f_fs: Fix Use-After-Free in AIO error path","CVE":"CVE-2026-90044","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"90044","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\nusb: gadget: f_fs: Fix Use-After-Free in AIO error path\n\nIn ffs_epfile_write_iter() and ffs_epfile_read_iter(), when ffs_epfile_io()\nfails with an error other than -EIOCBQUEUED, the io_data structure (`p`) is\nfreed. However, for AIO operations, the kiocb cancel function was already\narmed and kiocb->private was set to `p`.\n\nIf a concurrent cancel operation (such as sys_io_cancel()) executes after\nffs_epfile_io() fails but before the function frees `p`, a Use-After-Free\ncan occur when the cancellation handler accesses the freed pointer.\n\nTo securely fix this race condition, we must properly un-arm the\ncancellation. Invoking `kiocb->ki_complete()` does exactly this by\nacquiring `ctx->ctx_lock` and safely removing the kiocb from the active\nsequence. In doing so, it ensures that a parallel io_cancel can no longer\ndiscover the kiocb, effectively closing the race window.\n\nWe then return -EIOCBQUEUED to notify the VFS layer that the kiocb has been\nconsumed and it should avoid attempting to complete the request again or\ntriggering subsequent completion handlers.","Type":"Description","Title":"usb: gadget: f_fs: Fix Use-After-Free in AIO error path"}]}}}