{"id":"CVE-2025-68317","state":"PUBLISHED","title":"io_uring/zctx: check chained notif contexts","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nio_uring/zctx: check chained notif contexts\n\nSend zc only links ubuf_info for requests coming from the same context.\nThere are some ambiguous syz reports, so let's check the assumption on\nnotification completion.","publishedAt":"2025-12-16T15:39:47.159Z","updatedAt":"2026-10-15T22:02:49.138Z","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":"6fe4220912d19152a26ce19713ab232f4263018d","status":"affected","lessThan":"aaafd17d3f4be2c15539359a5b4bfa00237f687f","versionType":"git"},{"version":"6fe4220912d19152a26ce19713ab232f4263018d","status":"affected","lessThan":"d664a3ce3a604231a0b144c152a3755d03b18b60","versionType":"git"},{"version":"6fe4220912d19152a26ce19713ab232f4263018d","status":"affected","lessThan":"ab3ea6eac5f45669b091309f592c4ea324003053","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["io_uring/notif.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.10","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.10","versionType":"semver"},{"version":"6.12.58","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.17.8","status":"unaffected","lessThanOrEqual":"6.17.*","versionType":"semver"},{"version":"6.18","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["io_uring/notif.c"]}],"references":["https://git.kernel.org/stable/c/aaafd17d3f4be2c15539359a5b4bfa00237f687f","https://git.kernel.org/stable/c/d664a3ce3a604231a0b144c152a3755d03b18b60","https://git.kernel.org/stable/c/ab3ea6eac5f45669b091309f592c4ea324003053"],"weaknesses":[],"ingestedAt":"2026-10-29T20:09:56.034Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2025/68xxx/CVE-2025-68317.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2025-68317","state":"PUBLISHED","datePublished":"2025-12-16T15:39:47.159Z","dateUpdated":"2026-10-15T22:02:49.138Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2025-12-16T14:48:05.295Z"},"containers":{"cna":{"title":"io_uring/zctx: check chained notif contexts","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nio_uring/zctx: check chained notif contexts\n\nSend zc only links ubuf_info for requests coming from the same context.\nThere are some ambiguous syz reports, so let's check the assumption on\nnotification completion."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"6fe4220912d19152a26ce19713ab232f4263018d","status":"affected","lessThan":"aaafd17d3f4be2c15539359a5b4bfa00237f687f","versionType":"git"},{"version":"6fe4220912d19152a26ce19713ab232f4263018d","status":"affected","lessThan":"d664a3ce3a604231a0b144c152a3755d03b18b60","versionType":"git"},{"version":"6fe4220912d19152a26ce19713ab232f4263018d","status":"affected","lessThan":"ab3ea6eac5f45669b091309f592c4ea324003053","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["io_uring/notif.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.10","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.10","versionType":"semver"},{"version":"6.12.58","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.17.8","status":"unaffected","lessThanOrEqual":"6.17.*","versionType":"semver"},{"version":"6.18","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["io_uring/notif.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/aaafd17d3f4be2c15539359a5b4bfa00237f687f"},{"url":"https://git.kernel.org/stable/c/d664a3ce3a604231a0b144c152a3755d03b18b60"},{"url":"https://git.kernel.org/stable/c/ab3ea6eac5f45669b091309f592c4ea324003053"}],"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 - A local process reaches the flaw by submitting IORING_OP_SEND_ZC or IORING_OP_SENDMSG_ZC requests through io_uring. Remote packets alone cannot construct the required cross-ring notification chain.\nAC:L - The attacker can deterministically reuse a TCP skb with small sends and MSG_MORE across two attacker-created rings. Any completion-list race is attacker-controlled through concurrent submissions and ACK or socket timing.\nPR:L - Normal io_uring setup, TCP socket creation, and zero-copy sends require no capabilities when io_uring is enabled. An ordinary unprivileged account with a small buffer within RLIMIT_MEMLOCK can reach the flaw without user namespaces.\nUI:N - The attacker creates the rings, submits both sends, and causes skb completion without any victim action.\nS:U - The corruption affects the host kernel and represents a standard local privilege-escalation boundary rather than a VM, IOMMU, or other security-scope escape.\nC:H - Wrong-context completion modifies a foreign ring’s completion list without its mutex; racing a flush can corrupt its request free list and reallocate a still-linked notification, producing UAF and type confusion capable of kernel-memory disclosure. [NVD assigns C:H to the same root-cause defect](https://nvd.nist.gov/vuln/detail/CVE-2025-39963).\nI:H - The corrupted free list permits an active io_kiocb to be reused and subsequently interpreted as notification data, enabling kernel heap corruption and potentially arbitrary writes or control-flow hijacking.\nA:H - The wrong-lock completion has been observed by [syzkaller](https://syzkaller.appspot.com/bug?id=423c19d7bb9000c4ddc 1c63f9faface466fb6c35); without the diagnostic stopping execution, the resulting list corruption can cause an oops, panic, hang, or repeatable resource leak."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-08-05T12:10:50.931Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.10","versionEndExcluding":"6.12.58"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.10","versionEndExcluding":"6.17.8"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.10","versionEndExcluding":"6.18"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"id":"CVE-2025-68317","role":"CISA Coordinator","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"total"}],"version":"2.0.3","timestamp":"2026-10-15T22:00:54.118508Z"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-10-15T22:02:49.138Z"}}]}}}