{
    "dataType": "CVE_RECORD",
    "dataVersion": "5.2",
    "cveMetadata": {
        "cveId": "CVE-2026-63955",
        "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "state": "PUBLISHED",
        "assignerShortName": "Linux",
        "dateReserved": "2026-07-19T07:54:57.023Z",
        "datePublished": "2026-07-19T14:55:46.903Z",
        "dateUpdated": "2026-08-05T12:37:39.551Z"
    },
    "containers": {
        "cna": {
            "providerMetadata": {
                "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
                "shortName": "Linux",
                "dateUpdated": "2026-08-05T12:37:39.551Z"
            },
            "descriptions": [
                {
                    "lang": "en",
                    "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmm/vmalloc: do not trigger BUG() on BH disabled context\n\n__get_vm_area_node() currently triggers a BUG() if in_interrupt() returns\ntrue.  However, in_interrupt() also reports true when BH are disabled.\n\nThe bridge code can call rhashtable_lookup_insert_fast() with bottom\nhalves disabled:\n\n__vlan_add()\n -> br_fdb_add_local()\n  spin_lock_bh(&br->hash_lock); <-- Disable BH\n   -> fdb_add_local()\n    -> fdb_create()\n     -> rhashtable_lookup_insert_fast()\n      -> kvmalloc()\n       -> vmalloc()\n        -> __get_vm_area_node()\n         -> BUG_ON(in_interrupt())\n  spin_unlock_bh(&br->hash_lock)\n\nthis triggers the BUG() despite the caller not being in NMI or\nhard IRQ context.\n\nReplace the in_interrupt() check with in_nmi() || in_hardirq()."
                }
            ],
            "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 - After kvmalloc gained GFP_ATOMIC vmalloc fallback, reachable rhashtable resize paths run from network packet handling (e.g. bridge FDB learning in RX softirq, VXLAN UDP receive/snoop) and can call __get_vm_area_node() while in_interrupt() is true.\nAC:L - An attacker can reliably trigger the BUG by flooding a reachable bridge/VXLAN interface with many unique source MACs (or equivalent netlink admin operations) to force rhashtable growth and a large GFP_ATOMIC kvmalloc vmalloc fallback.\nPR:N - The highest-impact path needs no kernel privileges: sending crafted L2/overlay packets to a learning bridge or VXLAN endpoint is sufficient; netlink-only paths additionally require CAP_NET_ADMIN but are not the ceiling.\nUI:N - Exploitation is fully attacker-driven packet or netlink traffic and does not require any victim user action beyond normal system operation.\nS:U - Impact is a host kernel BUG/panic from the mm/vmalloc path; it does not cross a VM, IOMMU, or sandbox security boundary for privilege escalation.\nC:N - The failure mode is an intentional BUG_ON() kernel panic with no memory corruption, out-of-bounds access, or information disclosure primitive.\nI:N - No attacker-controlled memory is modified; the bug only aborts the kernel via BUG() rather than providing a write or code-execution primitive.\nA:H - Hitting BUG_ON(in_interrupt()) in __get_vm_area_node() causes a kernel BUG/oops/panic, producing total loss of system availability."
                        }
                    ]
                }
            ],
            "affected": [
                {
                    "product": "Linux",
                    "vendor": "Linux",
                    "defaultStatus": "unaffected",
                    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                    "programFiles": [
                        "mm/vmalloc.c"
                    ],
                    "versions": [
                        {
                            "version": "c6307674ed82c0c57d6e1e3408e84ac449ab8e94",
                            "lessThan": "ad7eff07b625f53c3fb513b30d7a8c5a79fbc7ce",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "c6307674ed82c0c57d6e1e3408e84ac449ab8e94",
                            "lessThan": "04aa71da5f35aacdc9ae9cb5150947daa624f641",
                            "status": "affected",
                            "versionType": "git"
                        }
                    ]
                },
                {
                    "product": "Linux",
                    "vendor": "Linux",
                    "defaultStatus": "affected",
                    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                    "programFiles": [
                        "mm/vmalloc.c"
                    ],
                    "versions": [
                        {
                            "version": "6.19",
                            "status": "affected"
                        },
                        {
                            "version": "0",
                            "lessThan": "6.19",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "7.0.12",
                            "lessThanOrEqual": "7.0.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "7.1",
                            "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": "6.19",
                                    "versionEndExcluding": "7.0.12"
                                },
                                {
                                    "vulnerable": true,
                                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                                    "versionStartIncluding": "6.19",
                                    "versionEndExcluding": "7.1"
                                }
                            ]
                        }
                    ]
                }
            ],
            "references": [
                {
                    "url": "https://git.kernel.org/stable/c/ad7eff07b625f53c3fb513b30d7a8c5a79fbc7ce"
                },
                {
                    "url": "https://git.kernel.org/stable/c/04aa71da5f35aacdc9ae9cb5150947daa624f641"
                }
            ],
            "title": "mm/vmalloc: do not trigger BUG() on BH disabled context",
            "x_generator": {
                "engine": "bippy-1.2.0"
            }
        }
    }
}