{"api_version":"1","generated_at":"2026-08-09T05:11:26+00:00","cve":"CVE-2026-64588","urls":{"html":"https://cve.report/CVE-2026-64588","api":"https://cve.report/api/cve/CVE-2026-64588.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-64588","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-64588"},"summary":{"title":"fuse-uring: fix data races on ring->ready","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nfuse-uring: fix data races on ring->ready\n\nOn weakly-ordered architectures, the store to fiq->ops can be\nreordered past the store to ring->ready, allowing a CPU that sees\nring->ready == true via fuse_uring_ready() to dispatch requests\nthrough a stale fiq->ops pointer. Upgrade the store to\nsmp_store_release() and the load in fuse_uring_ready() to\nsmp_load_acquire() so that the preceding WRITE_ONCE(fiq->ops, ...)\nis visible to any CPU that observes ring->ready == true.\n\nAdditionally, fuse_uring_do_register() publishes ring->ready with\nWRITE_ONCE() but the fast-path check reads it with a plain load.\nThis is a marked-vs-unmarked access that KCSAN will flag. Wrap it in\nREAD_ONCE() to mark it without adding unnecessary ordering.\n\nAlso wrap the fc->ring load in fuse_uring_ready() in READ_ONCE() to\nprevent the compiler from reloading it between the NULL check and the\ndereference.","state":"PUBLISHED","assigner":"Linux","published_at":"2026-08-06 08:16:34","updated_at":"2026-08-08 15:16:34"},"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/46725a0056c884cf58a6897f222892807327d82d","name":"https://git.kernel.org/stable/c/46725a0056c884cf58a6897f222892807327d82d","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/b156bb9966972122b148acab8bdf415cdb8176a3","name":"https://git.kernel.org/stable/c/b156bb9966972122b148acab8bdf415cdb8176a3","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/d01a09b442cb786cd44ccc7c84d57e2856d6737c","name":"https://git.kernel.org/stable/c/d01a09b442cb786cd44ccc7c84d57e2856d6737c","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-64588","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-64588","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected c2c9af9a0b13261c36909036057a116f2edb5e1a b156bb9966972122b148acab8bdf415cdb8176a3 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected c2c9af9a0b13261c36909036057a116f2edb5e1a d01a09b442cb786cd44ccc7c84d57e2856d6737c git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected c2c9af9a0b13261c36909036057a116f2edb5e1a 46725a0056c884cf58a6897f222892807327d82d git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 6.14","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.14 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18.39 6.18.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.1.4 7.1.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.2-rc1 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":{"cve_year":"2026","cve_id":"64588","cve":"CVE-2026-64588","epss":"0.001540000","percentile":"0.050910000","score_date":"2026-08-08","updated_at":"2026-08-09 00:07:22"},"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Linux","programFiles":["fs/fuse/dev_uring.c","fs/fuse/dev_uring_i.h"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"b156bb9966972122b148acab8bdf415cdb8176a3","status":"affected","version":"c2c9af9a0b13261c36909036057a116f2edb5e1a","versionType":"git"},{"lessThan":"d01a09b442cb786cd44ccc7c84d57e2856d6737c","status":"affected","version":"c2c9af9a0b13261c36909036057a116f2edb5e1a","versionType":"git"},{"lessThan":"46725a0056c884cf58a6897f222892807327d82d","status":"affected","version":"c2c9af9a0b13261c36909036057a116f2edb5e1a","versionType":"git"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["fs/fuse/dev_uring.c","fs/fuse/dev_uring_i.h"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"6.14"},{"lessThan":"6.14","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"6.18.*","status":"unaffected","version":"6.18.39","versionType":"semver"},{"lessThanOrEqual":"7.1.*","status":"unaffected","version":"7.1.4","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"7.2-rc1","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.18.39","versionStartIncluding":"6.14","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.1.4","versionStartIncluding":"6.14","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.2-rc1","versionStartIncluding":"6.14","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nfuse-uring: fix data races on ring->ready\n\nOn weakly-ordered architectures, the store to fiq->ops can be\nreordered past the store to ring->ready, allowing a CPU that sees\nring->ready == true via fuse_uring_ready() to dispatch requests\nthrough a stale fiq->ops pointer. Upgrade the store to\nsmp_store_release() and the load in fuse_uring_ready() to\nsmp_load_acquire() so that the preceding WRITE_ONCE(fiq->ops, ...)\nis visible to any CPU that observes ring->ready == true.\n\nAdditionally, fuse_uring_do_register() publishes ring->ready with\nWRITE_ONCE() but the fast-path check reads it with a plain load.\nThis is a marked-vs-unmarked access that KCSAN will flag. Wrap it in\nREAD_ONCE() to mark it without adding unnecessary ordering.\n\nAlso wrap the fc->ring load in fuse_uring_ready() in READ_ONCE() to\nprevent the compiler from reloading it between the NULL check and the\ndereference."}],"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 bug is reached locally by mounting FUSE with io-uring and submitting IORING_OP_URING_CMD registration while other local threads generate FUSE requests; no network protocol path invokes fuse_uring_ready() or fuse_uring_do_register().\nAC:L - The attacker controls both sides of the race by registering ring entries on /dev/fuse while concurrently issuing filesystem operations on the same mount, so the publish window on weakly ordered CPUs can be driven and retried without relying on victim state.\nPR:L - FUSE is FS_USERNS_MOUNT, so an ordinary user can create a user-namespace mount, open /dev/fuse, and enable FUSE_OVER_IO_URING without init-namespace root privileges.\nUI:N - The attacker can run both the FUSE daemon that registers io-uring queues and the client threads that generate requests on that mount, so no separate victim action is required.\nS:U - Impact is confined to the host kernel authority as a local FUSE/io-uring memory-safety failure, not a VM, IOMMU, or guest-to-host boundary escape.\nC:H - Missing acquire on ring->ready lets CPUs observe readiness while fiq->ops and related ring publication are stale, and the unfixed fc->ring reload in fuse_uring_ready() is a check-then-use UAF window against ring teardown, enabling disclosure of reclaimed kernel memory.\nI:H - Dispatching through inconsistent ops/ring state and the concurrent ring reload UAF allow writes and list/queue operations on stale or reallocated fuse_ring objects, which is exploitable for heap corruption and control-flow hijacking.\nA:H - The same races can NULL-dereference or use a freed fuse_ring in fuse_uring_task_to_queue()/fuse_uring_ready(), hang requests on the wrong queue path, and trigger WARN/oops or panic under panic_on_warn."}]}],"providerMetadata":{"dateUpdated":"2026-08-08T15:13:25.994Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/b156bb9966972122b148acab8bdf415cdb8176a3"},{"url":"https://git.kernel.org/stable/c/d01a09b442cb786cd44ccc7c84d57e2856d6737c"},{"url":"https://git.kernel.org/stable/c/46725a0056c884cf58a6897f222892807327d82d"}],"title":"fuse-uring: fix data races on ring->ready","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-64588","datePublished":"2026-08-06T07:13:46.688Z","dateReserved":"2026-07-19T15:36:31.798Z","dateUpdated":"2026-08-08T15:13:25.994Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-08-06 08:16:34","lastModifiedDate":"2026-08-08 15:16:34","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":"64588","Ordinal":"1","Title":"fuse-uring: fix data races on ring->ready","CVE":"CVE-2026-64588","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"64588","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\nfuse-uring: fix data races on ring->ready\n\nOn weakly-ordered architectures, the store to fiq->ops can be\nreordered past the store to ring->ready, allowing a CPU that sees\nring->ready == true via fuse_uring_ready() to dispatch requests\nthrough a stale fiq->ops pointer. Upgrade the store to\nsmp_store_release() and the load in fuse_uring_ready() to\nsmp_load_acquire() so that the preceding WRITE_ONCE(fiq->ops, ...)\nis visible to any CPU that observes ring->ready == true.\n\nAdditionally, fuse_uring_do_register() publishes ring->ready with\nWRITE_ONCE() but the fast-path check reads it with a plain load.\nThis is a marked-vs-unmarked access that KCSAN will flag. Wrap it in\nREAD_ONCE() to mark it without adding unnecessary ordering.\n\nAlso wrap the fc->ring load in fuse_uring_ready() in READ_ONCE() to\nprevent the compiler from reloading it between the NULL check and the\ndereference.","Type":"Description","Title":"fuse-uring: fix data races on ring->ready"}]}}}