{"id":"CVE-2026-43366","state":"PUBLISHED","title":"io_uring/kbuf: check if target buffer list is still legacy on recycle","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nio_uring/kbuf: check if target buffer list is still legacy on recycle\n\nThere's a gap between when the buffer was grabbed and when it\npotentially gets recycled, where if the list is empty, someone could've\nupgraded it to a ring provided type. This can happen if the request\nis forced via io-wq. The legacy recycling is missing checking if the\nbuffer_list still exists, and if it's of the correct type. Add those\nchecks.","publishedAt":"2026-05-08T14:21:19.191Z","updatedAt":"2026-10-19T19:16:27.613Z","severity":{"score":7.8,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","source":"Linux"},"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"c7fb19428d67dd0a2a78a4f237af01d39c78dc5a","status":"affected","lessThan":"a7b33671e418fca507feebd1d56e7f4952a4b25c","versionType":"git"},{"version":"c7fb19428d67dd0a2a78a4f237af01d39c78dc5a","status":"affected","lessThan":"439a6728ec4641ffad1ca796622c19bc525e570f","versionType":"git"},{"version":"c7fb19428d67dd0a2a78a4f237af01d39c78dc5a","status":"affected","lessThan":"f3fb54e7a8b4aadcc2836ee463eec8c88709b8aa","versionType":"git"},{"version":"c7fb19428d67dd0a2a78a4f237af01d39c78dc5a","status":"affected","lessThan":"50ad880db3013c6fee0ef13781762a39e2e7ef83","versionType":"git"},{"version":"c7fb19428d67dd0a2a78a4f237af01d39c78dc5a","status":"affected","lessThan":"97b57f69fee1b61b41acbf37e7720cac9d389fa4","versionType":"git"},{"version":"c7fb19428d67dd0a2a78a4f237af01d39c78dc5a","status":"affected","lessThan":"c2c185be5c85d37215397c8e8781abf0a69bec1f","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["io_uring/kbuf.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"5.19","status":"affected"},{"version":"0","status":"unaffected","lessThan":"5.19","versionType":"semver"},{"version":"6.1.167","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.130","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.78","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.19","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"6.19.9","status":"unaffected","lessThanOrEqual":"6.19.*","versionType":"semver"},{"version":"7.0","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["io_uring/kbuf.c"]}],"references":["https://git.kernel.org/stable/c/a7b33671e418fca507feebd1d56e7f4952a4b25c","https://git.kernel.org/stable/c/439a6728ec4641ffad1ca796622c19bc525e570f","https://git.kernel.org/stable/c/f3fb54e7a8b4aadcc2836ee463eec8c88709b8aa","https://git.kernel.org/stable/c/50ad880db3013c6fee0ef13781762a39e2e7ef83","https://git.kernel.org/stable/c/97b57f69fee1b61b41acbf37e7720cac9d389fa4","https://git.kernel.org/stable/c/c2c185be5c85d37215397c8e8781abf0a69bec1f"],"weaknesses":["CWE-362"],"ingestedAt":"2026-10-29T20:11:57.932Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/43xxx/CVE-2026-43366.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-43366","state":"PUBLISHED","datePublished":"2026-05-08T14:21:19.191Z","dateUpdated":"2026-10-19T19:16:27.613Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-05-01T14:12:56.005Z"},"containers":{"cna":{"title":"io_uring/kbuf: check if target buffer list is still legacy on recycle","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nio_uring/kbuf: check if target buffer list is still legacy on recycle\n\nThere's a gap between when the buffer was grabbed and when it\npotentially gets recycled, where if the list is empty, someone could've\nupgraded it to a ring provided type. This can happen if the request\nis forced via io-wq. The legacy recycling is missing checking if the\nbuffer_list still exists, and if it's of the correct type. Add those\nchecks."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"c7fb19428d67dd0a2a78a4f237af01d39c78dc5a","status":"affected","lessThan":"a7b33671e418fca507feebd1d56e7f4952a4b25c","versionType":"git"},{"version":"c7fb19428d67dd0a2a78a4f237af01d39c78dc5a","status":"affected","lessThan":"439a6728ec4641ffad1ca796622c19bc525e570f","versionType":"git"},{"version":"c7fb19428d67dd0a2a78a4f237af01d39c78dc5a","status":"affected","lessThan":"f3fb54e7a8b4aadcc2836ee463eec8c88709b8aa","versionType":"git"},{"version":"c7fb19428d67dd0a2a78a4f237af01d39c78dc5a","status":"affected","lessThan":"50ad880db3013c6fee0ef13781762a39e2e7ef83","versionType":"git"},{"version":"c7fb19428d67dd0a2a78a4f237af01d39c78dc5a","status":"affected","lessThan":"97b57f69fee1b61b41acbf37e7720cac9d389fa4","versionType":"git"},{"version":"c7fb19428d67dd0a2a78a4f237af01d39c78dc5a","status":"affected","lessThan":"c2c185be5c85d37215397c8e8781abf0a69bec1f","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["io_uring/kbuf.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"5.19","status":"affected"},{"version":"0","status":"unaffected","lessThan":"5.19","versionType":"semver"},{"version":"6.1.167","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.130","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.78","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.19","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"6.19.9","status":"unaffected","lessThanOrEqual":"6.19.*","versionType":"semver"},{"version":"7.0","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["io_uring/kbuf.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/a7b33671e418fca507feebd1d56e7f4952a4b25c"},{"url":"https://git.kernel.org/stable/c/439a6728ec4641ffad1ca796622c19bc525e570f"},{"url":"https://git.kernel.org/stable/c/f3fb54e7a8b4aadcc2836ee463eec8c88709b8aa"},{"url":"https://git.kernel.org/stable/c/50ad880db3013c6fee0ef13781762a39e2e7ef83"},{"url":"https://git.kernel.org/stable/c/97b57f69fee1b61b41acbf37e7720cac9d389fa4"},{"url":"https://git.kernel.org/stable/c/c2c185be5c85d37215397c8e8781abf0a69bec1f"}],"metrics":[{"cvssV3_1":{"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"},"scenarios":[{"lang":"en","value":"AV:L - The vulnerable code is reachable through local `io_uring_setup`, `io_uring_enter`, and `io_uring_register` operations using provided buffer selection and buffer-ring registration. It is not directly reachable from network packets or physical/adjacent interfaces.\nAC:L - The attacker controls the io_uring ring, the legacy provided buffer group, the in-flight async/io-wq request, and the conversion/removal of the same buffer group. The required timing can be driven by attacker-controlled concurrent local operations, so the race/lifecycle window is low complexity.\nPR:L - Exploitation requires a local unprivileged user able to create and use an io_uring instance; the relevant setup/register/submit paths do not require real root or init-namespace capabilities when io_uring is enabled. This is basic local user privilege, not administrator privilege.\nUI:N - No victim action is required after the attacker runs local code. The attacker performs all setup, submission, and buffer group conversion operations directly.\nS:U - The bug corrupts kernel memory from within the kernel/io_uring security authority and can lead to local kernel compromise or crash. It does not inherently cross a VM, IOMMU, or separate authorization boundary.\nC:H - The legacy recycle path can type-confuse a ring-provided buffer list and write kernel pointers into attacker-observable ring memory, and subsequent use can treat attacker-influenced objects as buffer-ring state. This is kernel memory corruption with a defensible path to high confidentiality impact.\nI:H - Recycling a legacy `struct io_buffer` into a ring buffer list corrupts list/ring state and can turn later ring-buffer operations into controlled kernel memory misuse. As a type confusion/memory corruption bug, high integrity impact is appropriate.\nA:H - If the target buffer list has been removed the old code can dereference a NULL buffer-list pointer, and if it has been upgraded it corrupts kernel state. Either case can produce an oops/panic or otherwise destabilize the kernel."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-08-05T12:27:30.302Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.19","versionEndExcluding":"6.1.167"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.19","versionEndExcluding":"6.6.130"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.19","versionEndExcluding":"6.12.78"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.19","versionEndExcluding":"6.18.19"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.19","versionEndExcluding":"6.19.9"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.19","versionEndExcluding":"7.0"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"id":"CVE-2026-43366","role":"CISA Coordinator","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"total"}],"version":"2.0.3","timestamp":"2026-10-16T15:16:47.117231Z"}}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-362","lang":"en","type":"CWE","description":"CWE-362 Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')"}]}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-10-19T19:16:27.613Z"}}]}}}