{
    "dataType": "CVE_RECORD",
    "dataVersion": "5.2",
    "cveMetadata": {
        "cveId": "CVE-2026-31640",
        "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "state": "PUBLISHED",
        "assignerShortName": "Linux",
        "dateReserved": "2026-03-09T15:48:24.125Z",
        "datePublished": "2026-04-24T14:44:54.024Z",
        "dateUpdated": "2026-08-05T12:24:04.294Z"
    },
    "containers": {
        "cna": {
            "providerMetadata": {
                "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
                "shortName": "Linux",
                "dateUpdated": "2026-08-05T12:24:04.294Z"
            },
            "descriptions": [
                {
                    "lang": "en",
                    "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nrxrpc: Fix use of wrong skb when comparing queued RESP challenge serial\n\nIn rxrpc_post_response(), the code should be comparing the challenge serial\nnumber from the cached response before deciding to switch to a newer\nresponse, but looks at the newer packet private data instead, rendering the\ncomparison always false.\n\nFix this by switching to look at the older packet.\n\nFix further[1] to substitute the new packet in place of the old one if\nnewer and also to release whichever we don't use."
                }
            ],
            "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 rxrpc path is reached by received RxRPC CHALLENGE packets over UDP from a remote peer to an existing client connection.\nAC:L - An attacker controlling the remote RxRPC peer can send bursts of well-formed CHALLENGE packets and controls the relevant timing pressure; no rare configuration or uncontrollable race is required beyond normal RxRPC use.\nPR:N - The attacker does not need credentials on the victim; challenge validation checks packet structure/key state but does not authenticate the remote sender before reaching the vulnerable response queuing path.\nUI:N - Once the victim has an RxRPC/AFS client connection to the remote peer, exploitation is driven by network packets and requires no further victim action.\nS:U - The impact is within the kernel/networking subsystem on the same host and does not cross a VM, IOMMU, or other separate security authority boundary.\nC:N - The bug leaks kernel skb allocations internally and may send a stale response, but it does not provide an attacker-visible memory disclosure or read primitive.\nI:N - The faulty comparison/queue replacement does not corrupt attacker-chosen memory or permit data modification; it only preserves the wrong queued response and loses references to newer ones.\nA:H - Repeated remote CHALLENGE bursts can permanently leak RESPONSE skbs and cause authentication failures, making kernel memory exhaustion and service denial a defensible high availability impact."
                        }
                    ]
                }
            ],
            "affected": [
                {
                    "product": "Linux",
                    "vendor": "Linux",
                    "defaultStatus": "unaffected",
                    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                    "programFiles": [
                        "include/trace/events/rxrpc.h",
                        "net/rxrpc/conn_event.c"
                    ],
                    "versions": [
                        {
                            "version": "5800b1cf3fd8ccab752a101865be1e76dac33142",
                            "lessThan": "9132b1a7bf83b4a8042fffbc99d075b727a16742",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "5800b1cf3fd8ccab752a101865be1e76dac33142",
                            "lessThan": "20386e7f8d97475b8d815873e246423317ec4260",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "5800b1cf3fd8ccab752a101865be1e76dac33142",
                            "lessThan": "b33f5741bb187db8ff32e8f5b96def77cc94dfca",
                            "status": "affected",
                            "versionType": "git"
                        }
                    ]
                },
                {
                    "product": "Linux",
                    "vendor": "Linux",
                    "defaultStatus": "affected",
                    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                    "programFiles": [
                        "include/trace/events/rxrpc.h",
                        "net/rxrpc/conn_event.c"
                    ],
                    "versions": [
                        {
                            "version": "6.16",
                            "status": "affected"
                        },
                        {
                            "version": "0",
                            "lessThan": "6.16",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "6.18.23",
                            "lessThanOrEqual": "6.18.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "6.19.13",
                            "lessThanOrEqual": "6.19.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "7.0",
                            "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": "6.18.23"
                                },
                                {
                                    "vulnerable": true,
                                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                                    "versionStartIncluding": "6.16",
                                    "versionEndExcluding": "6.19.13"
                                },
                                {
                                    "vulnerable": true,
                                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                                    "versionStartIncluding": "6.16",
                                    "versionEndExcluding": "7.0"
                                }
                            ]
                        }
                    ]
                }
            ],
            "references": [
                {
                    "url": "https://git.kernel.org/stable/c/9132b1a7bf83b4a8042fffbc99d075b727a16742"
                },
                {
                    "url": "https://git.kernel.org/stable/c/20386e7f8d97475b8d815873e246423317ec4260"
                },
                {
                    "url": "https://git.kernel.org/stable/c/b33f5741bb187db8ff32e8f5b96def77cc94dfca"
                }
            ],
            "title": "rxrpc: Fix use of wrong skb when comparing queued RESP challenge serial",
            "x_generator": {
                "engine": "bippy-1.2.0"
            }
        }
    }
}