{
    "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"
            }
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    }
}