{
    "dataType": "CVE_RECORD",
    "dataVersion": "5.2",
    "cveMetadata": {
        "cveId": "CVE-2025-39962",
        "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "state": "PUBLISHED",
        "assignerShortName": "Linux",
        "dateReserved": "2025-04-16T07:20:57.149Z",
        "datePublished": "2025-10-09T12:13:22.684Z",
        "dateUpdated": "2026-08-05T12:06:31.023Z"
    },
    "containers": {
        "cna": {
            "providerMetadata": {
                "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
                "shortName": "Linux",
                "dateUpdated": "2026-08-05T12:06:31.023Z"
            },
            "descriptions": [
                {
                    "lang": "en",
                    "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nrxrpc: Fix untrusted unsigned subtract\n\nFix the following Smatch static checker warning:\n\n   net/rxrpc/rxgk_app.c:65 rxgk_yfs_decode_ticket()\n   warn: untrusted unsigned subtract. 'ticket_len - 10 * 4'\n\nby prechecking the length of what we're trying to extract in two places in\nthe token and decoding for a response packet.\n\nAlso use sizeof() on the struct we're extracting rather specifying the size\nnumerically to be consistent with the other related statements."
                }
            ],
            "metrics": [
                {
                    "cvssV3_1": {
                        "version": "3.1",
                        "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
                        "baseScore": 7.5,
                        "baseSeverity": "HIGH"
                    },
                    "scenarios": [
                        {
                            "lang": "en",
                            "value": "AV:N - The vulnerable code parses RxGK RESPONSE packets received over UDP by an rxrpc server connection; the AFS cache manager (present on every kafs client) exposes this path to remote peers on the network.\nAC:L - A single crafted RESPONSE packet with a small token_len and oversized ticket_len reliably bypasses the check and triggers the crash; the required server key exists by default on the CM and kvno/enctype are standard, with no attacker-uncontrolled conditions.\nPR:N - The malformed length is processed during the challenge/response handshake (CONN_SERVICE_CHALLENGING), before any credential is verified, so no authentication or privileges are required.\nUI:N - Exploitation is fully driven by attacker-sent network packets; no action by any local user is needed.\nS:U - The impact is confined to the kernel that processes the packet; no crossing of a security/authority boundary such as VM or IOMMU escape occurs.\nC:N - The reliably reachable path is a BUG_ON crash with no data returned to the attacker; the OOB-read variant requires server-key knowledge to control decrypted content and its data is stored in a no-leak key, so there is no defensible information disclosure.\nI:N - The reachable outcome is a kernel panic in skb_to_sgvec; the length-check bypass does not yield an attacker-controlled write primitive (the payload allocation scales with the corrupted length), so no data modification results.\nA:H - The oversized attacker-controlled length reaches skb_to_sgvec and triggers BUG_ON(len), causing a kernel panic — a remote, unauthenticated denial of service."
                        }
                    ]
                }
            ],
            "affected": [
                {
                    "product": "Linux",
                    "vendor": "Linux",
                    "defaultStatus": "unaffected",
                    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                    "programFiles": [
                        "net/rxrpc/rxgk_app.c"
                    ],
                    "versions": [
                        {
                            "version": "9d1d2b59341f58126a69b51f9f5f8ccb9f12e54a",
                            "lessThan": "71571e187106631a8127f2dde780f35caa358d33",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "9d1d2b59341f58126a69b51f9f5f8ccb9f12e54a",
                            "lessThan": "2429a197648178cd4dc930a9d87c13c547460564",
                            "status": "affected",
                            "versionType": "git"
                        }
                    ]
                },
                {
                    "product": "Linux",
                    "vendor": "Linux",
                    "defaultStatus": "affected",
                    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                    "programFiles": [
                        "net/rxrpc/rxgk_app.c"
                    ],
                    "versions": [
                        {
                            "version": "6.16",
                            "status": "affected"
                        },
                        {
                            "version": "0",
                            "lessThan": "6.16",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "6.16.9",
                            "lessThanOrEqual": "6.16.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "6.17",
                            "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": "6.16",
                                    "versionEndExcluding": "6.16.9"
                                },
                                {
                                    "vulnerable": true,
                                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                                    "versionStartIncluding": "6.16",
                                    "versionEndExcluding": "6.17"
                                }
                            ]
                        }
                    ]
                }
            ],
            "references": [
                {
                    "url": "https://git.kernel.org/stable/c/71571e187106631a8127f2dde780f35caa358d33"
                },
                {
                    "url": "https://git.kernel.org/stable/c/2429a197648178cd4dc930a9d87c13c547460564"
                }
            ],
            "title": "rxrpc: Fix untrusted unsigned subtract",
            "x_generator": {
                "engine": "bippy-1.2.0"
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        }
    }
}