{"id":"CVE-2026-90095","state":"PUBLISHED","title":"fuse: Fix the condition to enable over-io-uring","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nfuse: Fix the condition to enable over-io-uring\n\nThe existing condition in fuse_uring_cmd() is there only to avoid\ndisabling io-uring for connections that already run with it, missing\nwas a condition to refuse any IORING_OP_URING_CMD if the\nconnection/channel didn't get enabled because of missing FUSE_INIT\nreply flag FUSE_OVER_IO_URING. Without the reply flag the barrier in\nfuse_uring_ready() doesn't work and IO could already be going on and\ncause deadlock states (at a minimum one between fch->bg_lock and\nqueue->lock).\n\nThe change itself is trivial, but brings behavior change,\nFUSE_OVER_IO_URING has to be set in the FUSE_INIT_REPLY by fuse servers\nto accept any IORING_OP_URING_CMD. Libfuse does that and the only\nnon-libfuse implementation I found (fractal-fuse) also does it.\nQemu patches for fuse-io-uring are not merged yet, as far as I know.\n\nMoved up is the smp_load_acquire(&fch->initialized) check, as a\nfuse-server implementation might try to setup io-uring before FUSE_INIT\nis processed and might have gotten -EOPNOTSUPP instead of -EAGAIN.\n\nAlso fixed is a stale comment that explains the handling of the\nFUSE_OVER_IO_URING flag in early RFC versions.\n\nIf there should be a report from any library or application we\nprobably need to revert this commit.","publishedAt":"2026-09-17T16:06:08.197Z","updatedAt":"2026-10-19T08:57:53.596Z","severity":null,"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"3393ff964e0fa5def66570c54a4612bf9df06b76","status":"affected","lessThan":"1ca1df82d9248fc0b5ff17d45607484f18e5d60b","versionType":"git"},{"version":"3393ff964e0fa5def66570c54a4612bf9df06b76","status":"affected","lessThan":"8f9a725d89711ad027f6b7183586ef91528f106d","versionType":"git"},{"version":"3393ff964e0fa5def66570c54a4612bf9df06b76","status":"affected","lessThan":"1f59015e958174e89be58cc8db16d70a60d17255","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/fuse/dev_uring.c","fs/fuse/inode.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.14","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.14","versionType":"semver"},{"version":"6.18.57","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.6","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":["fs/fuse/dev_uring.c","fs/fuse/inode.c"]}],"references":["https://git.kernel.org/stable/c/1ca1df82d9248fc0b5ff17d45607484f18e5d60b","https://git.kernel.org/stable/c/8f9a725d89711ad027f6b7183586ef91528f106d","https://git.kernel.org/stable/c/1f59015e958174e89be58cc8db16d70a60d17255"],"weaknesses":[],"ingestedAt":"2026-10-29T20:13:34.582Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/90xxx/CVE-2026-90095.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-90095","state":"PUBLISHED","datePublished":"2026-09-17T16:06:08.197Z","dateUpdated":"2026-10-19T08:57:53.596Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-09-11T19:38:34.786Z"},"containers":{"cna":{"title":"fuse: Fix the condition to enable over-io-uring","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nfuse: Fix the condition to enable over-io-uring\n\nThe existing condition in fuse_uring_cmd() is there only to avoid\ndisabling io-uring for connections that already run with it, missing\nwas a condition to refuse any IORING_OP_URING_CMD if the\nconnection/channel didn't get enabled because of missing FUSE_INIT\nreply flag FUSE_OVER_IO_URING. Without the reply flag the barrier in\nfuse_uring_ready() doesn't work and IO could already be going on and\ncause deadlock states (at a minimum one between fch->bg_lock and\nqueue->lock).\n\nThe change itself is trivial, but brings behavior change,\nFUSE_OVER_IO_URING has to be set in the FUSE_INIT_REPLY by fuse servers\nto accept any IORING_OP_URING_CMD. Libfuse does that and the only\nnon-libfuse implementation I found (fractal-fuse) also does it.\nQemu patches for fuse-io-uring are not merged yet, as far as I know.\n\nMoved up is the smp_load_acquire(&fch->initialized) check, as a\nfuse-server implementation might try to setup io-uring before FUSE_INIT\nis processed and might have gotten -EOPNOTSUPP instead of -EAGAIN.\n\nAlso fixed is a stale comment that explains the handling of the\nFUSE_OVER_IO_URING flag in early RFC versions.\n\nIf there should be a report from any library or application we\nprobably need to revert this commit."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"3393ff964e0fa5def66570c54a4612bf9df06b76","status":"affected","lessThan":"1ca1df82d9248fc0b5ff17d45607484f18e5d60b","versionType":"git"},{"version":"3393ff964e0fa5def66570c54a4612bf9df06b76","status":"affected","lessThan":"8f9a725d89711ad027f6b7183586ef91528f106d","versionType":"git"},{"version":"3393ff964e0fa5def66570c54a4612bf9df06b76","status":"affected","lessThan":"1f59015e958174e89be58cc8db16d70a60d17255","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/fuse/dev_uring.c","fs/fuse/inode.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.14","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.14","versionType":"semver"},{"version":"6.18.57","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.6","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":["fs/fuse/dev_uring.c","fs/fuse/inode.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/1ca1df82d9248fc0b5ff17d45607484f18e5d60b"},{"url":"https://git.kernel.org/stable/c/8f9a725d89711ad027f6b7183586ef91528f106d"},{"url":"https://git.kernel.org/stable/c/1f59015e958174e89be58cc8db16d70a60d17255"}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-10-19T08:57:53.596Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.14","versionEndExcluding":"6.18.57"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.14","versionEndExcluding":"7.2.6"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.14","versionEndExcluding":"7.3"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}