{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2025-68317","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2025-12-16T14:48:05.295Z","datePublished":"2025-12-16T15:39:47.159Z","dateUpdated":"2026-08-05T12:10:50.931Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-08-05T12:10:50.931Z"},"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."}],"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."}]}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["io_uring/notif.c"],"versions":[{"version":"6fe4220912d19152a26ce19713ab232f4263018d","lessThan":"aaafd17d3f4be2c15539359a5b4bfa00237f687f","status":"affected","versionType":"git"},{"version":"6fe4220912d19152a26ce19713ab232f4263018d","lessThan":"d664a3ce3a604231a0b144c152a3755d03b18b60","status":"affected","versionType":"git"},{"version":"6fe4220912d19152a26ce19713ab232f4263018d","lessThan":"ab3ea6eac5f45669b091309f592c4ea324003053","status":"affected","versionType":"git"}]},{"product":"Linux","vendor":"Linux","defaultStatus":"affected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["io_uring/notif.c"],"versions":[{"version":"6.10","status":"affected"},{"version":"0","lessThan":"6.10","status":"unaffected","versionType":"semver"},{"version":"6.12.58","lessThanOrEqual":"6.12.*","status":"unaffected","versionType":"semver"},{"version":"6.17.8","lessThanOrEqual":"6.17.*","status":"unaffected","versionType":"semver"},{"version":"6.18","lessThanOrEqual":"*","status":"unaffected","versionType":"original_commit_for_fix"}]}],"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"}]}]}],"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"}],"title":"io_uring/zctx: check chained notif contexts","x_generator":{"engine":"bippy-1.2.0"}}}}