{
    "dataType": "CVE_RECORD",
    "dataVersion": "5.2",
    "cveMetadata": {
        "cveId": "CVE-2026-99041",
        "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "state": "PUBLISHED",
        "assignerShortName": "Linux",
        "dateReserved": "2026-09-25T10:25:14.387Z",
        "datePublished": "2026-10-23T12:22:00.403Z",
        "dateUpdated": "2026-10-23T12:22:00.403Z"
    },
    "containers": {
        "cna": {
            "providerMetadata": {
                "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
                "shortName": "Linux",
                "dateUpdated": "2026-10-23T12:22:00.403Z"
            },
            "descriptions": [
                {
                    "lang": "en",
                    "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nip6_gre: remove obsolete ERSPAN PMTU update\n\nA tc tunnel_key action can attach a METADATA_IP_TUNNEL dst to an skb,\nand mirred can redirect it to a native ip6erspan device. The legacy PMTU\nupdate in ip6erspan_tunnel_xmit() treats that metadata dst as a route.\nSince it has no output device, dst_dev(dst)->mtu dereferences NULL.\n\nOn v7.2 with KASAN, an initial UID/GID 65534 process with CapEff 0 used\nself-created user and network namespaces to trigger:\n\n  KASAN: null-ptr-deref\n  RIP: ip6erspan_tunnel_xmit+0x10fc/0x2cc0\n  Kernel panic - not syncing: Fatal exception in interrupt\n\nThe update is obsolete. Commit fe1a4ca0a2b7 (\"ip6_gre: process toobig\nin a better way\") changed IPv6 GRE Too Big handling to update the\nunderlay route and removed the equivalent block from __gre6_xmit().\nip6_tnl_xmit() then propagates the underlay PMTU to the overlay route.\n\nRemove the stale ERSPAN copy and its now-unused dst variable. This\neliminates the metadata-dst dereference and keeps ERSPAN aligned with\nIPv6 GRE PMTU handling."
                }
            ],
            "affected": [
                {
                    "product": "Linux",
                    "vendor": "Linux",
                    "defaultStatus": "unaffected",
                    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                    "programFiles": [
                        "net/ipv6/ip6_gre.c"
                    ],
                    "versions": [
                        {
                            "version": "5a963eb61b7c39e6c422b6e48619d19d04719358",
                            "lessThan": "b14a682ad7d45345701e08f9279d483a1da8b36c",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "5a963eb61b7c39e6c422b6e48619d19d04719358",
                            "lessThan": "f5b143f4cd3fb7673df8d727550478a4b762908a",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "5a963eb61b7c39e6c422b6e48619d19d04719358",
                            "lessThan": "2d06cb25a497d3a7034ef9d172626c2d6620a0f1",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "5a963eb61b7c39e6c422b6e48619d19d04719358",
                            "lessThan": "8f27260b989f488760289276377db24fbfb20bfa",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "5a963eb61b7c39e6c422b6e48619d19d04719358",
                            "lessThan": "8bc60db48e8cba35488bbd6e1f94aa990afa275a",
                            "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/ipv6/ip6_gre.c"
                    ],
                    "versions": [
                        {
                            "version": "4.16",
                            "status": "affected"
                        },
                        {
                            "version": "0",
                            "lessThan": "4.16",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "6.6.160",
                            "lessThanOrEqual": "6.6.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "6.12.114",
                            "lessThanOrEqual": "6.12.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "6.18.58",
                            "lessThanOrEqual": "6.18.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "7.2.11",
                            "lessThanOrEqual": "7.2.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "7.3",
                            "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": "4.16",
                                    "versionEndExcluding": "6.6.160"
                                },
                                {
                                    "vulnerable": true,
                                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                                    "versionStartIncluding": "4.16",
                                    "versionEndExcluding": "6.12.114"
                                },
                                {
                                    "vulnerable": true,
                                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                                    "versionStartIncluding": "4.16",
                                    "versionEndExcluding": "6.18.58"
                                },
                                {
                                    "vulnerable": true,
                                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                                    "versionStartIncluding": "4.16",
                                    "versionEndExcluding": "7.2.11"
                                },
                                {
                                    "vulnerable": true,
                                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                                    "versionStartIncluding": "4.16",
                                    "versionEndExcluding": "7.3"
                                }
                            ]
                        }
                    ]
                }
            ],
            "references": [
                {
                    "url": "https://git.kernel.org/stable/c/b14a682ad7d45345701e08f9279d483a1da8b36c"
                },
                {
                    "url": "https://git.kernel.org/stable/c/f5b143f4cd3fb7673df8d727550478a4b762908a"
                },
                {
                    "url": "https://git.kernel.org/stable/c/2d06cb25a497d3a7034ef9d172626c2d6620a0f1"
                },
                {
                    "url": "https://git.kernel.org/stable/c/8f27260b989f488760289276377db24fbfb20bfa"
                },
                {
                    "url": "https://git.kernel.org/stable/c/8bc60db48e8cba35488bbd6e1f94aa990afa275a"
                }
            ],
            "title": "ip6_gre: remove obsolete ERSPAN PMTU update",
            "x_generator": {
                "engine": "bippy-1.2.0"
            }
        }
    }
}