CVE-2026-63955

{"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"}}}}

{}

{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "product": "Linux", "programFiles": ["mm/vmalloc.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"lessThan": "ad7eff07b625f53c3fb513b30d7a8c5a79fbc7ce", "status": "affected", "version": "c6307674ed82c0c57d6e1e3408e84ac449ab8e94", "versionType": "git"}, {"lessThan": "04aa71da5f35aacdc9ae9cb5150947daa624f641", "status": "affected", "version": "c6307674ed82c0c57d6e1e3408e84ac449ab8e94", "versionType": "git"}]}, {"defaultStatus": "affected", "product": "Linux", "programFiles": ["mm/vmalloc.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"status": "affected", "version": "6.19"}, {"lessThan": "6.19", "status": "unaffected", "version": "0", "versionType": "semver"}, {"lessThanOrEqual": "7.0.*", "status": "unaffected", "version": "7.0.12", "versionType": "semver"}, {"lessThanOrEqual": "*", "status": "unaffected", "version": "7.1", "versionType": "original_commit_for_fix"}]}], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}], "configurations": [{"nodes": [{"cpeMatch": [{"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "matchCriteriaId": "9161A938-0FA8-44BC-95FE-C5A271601AB3", "versionEndExcluding": "7.0.12", "versionStartIncluding": "6.19", "vulnerable": true}, {"criteria": "cpe:2.3:o:linux:linux_kernel:7.1:rc1:*:*:*:*:*:*", "matchCriteriaId": "B1EF7059-E670-45F4-B422-54C40FA86390", "vulnerable": true}, {"criteria": "cpe:2.3:o:linux:linux_kernel:7.1:rc2:*:*:*:*:*:*", "matchCriteriaId": "0D38F0BF-A728-4133-A358-D44A2F7EE6D6", "vulnerable": true}, {"criteria": "cpe:2.3:o:linux:linux_kernel:7.1:rc3:*:*:*:*:*:*", "matchCriteriaId": "EC732D08-5F7B-46D9-B154-E60C7F4F0A97", "vulnerable": true}, {"criteria": "cpe:2.3:o:linux:linux_kernel:7.1:rc4:*:*:*:*:*:*", "matchCriteriaId": "E5910A9D-F60A-409A-B486-FE66BFEBA9B9", "vulnerable": true}, {"criteria": "cpe:2.3:o:linux:linux_kernel:7.1:rc5:*:*:*:*:*:*", "matchCriteriaId": "81DFF19E-9CF8-49C6-8C36-1E4038622933", "vulnerable": true}], "negate": false, "operator": "OR"}]}], "cveTags": [], "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()."}], "id": "CVE-2026-63955", "lastModified": "2026-10-30T14:32:54.370", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "HIGH", "baseScore": 7.5, "baseSeverity": "HIGH", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H", "version": "3.1"}, "exploitabilityScore": 3.9, "impactScore": 3.6, "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "type": "Secondary"}]}, "published": "2026-07-19T16:17:14.307", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/04aa71da5f35aacdc9ae9cb5150947daa624f641"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/ad7eff07b625f53c3fb513b30d7a8c5a79fbc7ce"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Analyzed", "weaknesses": [{"description": [{"lang": "en", "value": "NVD-CWE-noinfo"}], "source": "nvd@nist.gov", "type": "Primary"}]}

{"bugzilla": {"description": "kernel: mm/vmalloc: do not trigger BUG() on BH disabled context", "id": "2502436", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2502436"}, "csaw": false, "cvss3": {"cvss3_base_score": "5.5", "cvss3_scoring_vector": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H", "status": "draft"}, "cwe": "CWE-617", "details": ["In the Linux kernel, the following vulnerability has been resolved:\nmm/vmalloc: do not trigger BUG() on BH disabled context\n__get_vm_area_node() currently triggers a BUG() if in_interrupt() returns\ntrue. However, in_interrupt() also reports true when BH are disabled.\nThe bridge code can call rhashtable_lookup_insert_fast() with bottom\nhalves disabled:\n__vlan_add()\n-> br_fdb_add_local()\nspin_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())\nspin_unlock_bh(&br->hash_lock)\nthis triggers the BUG() despite the caller not being in NMI or\nhard IRQ context.\nReplace the in_interrupt() check with in_nmi() || in_hardirq().", "A flaw was found in the Linux kernel's memory management. This vulnerability could lead to a system crash, making the system unavailable. The issue arises from an incorrect check within the kernel's virtual memory allocation process, which mistakenly triggers a system halt under certain conditions. An attacker could potentially exploit this flaw to cause a Denial of Service (DoS)."], "name": "CVE-2026-63955", "package_state": [{"cpe": "cpe:/o:redhat:enterprise_linux:10", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 10"}, {"cpe": "cpe:/o:redhat:enterprise_linux:6", "fix_state": "Out of support scope", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 6"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Not affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Not affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Not affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 9"}], "public_date": "2026-07-19T00:00:00Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-63955\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-63955\nhttps://lore.kernel.org/linux-cve-announce/2026071956-CVE-2026-63955-bf37@gregkh/T"], "threat_severity": "Low"}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[c6307674ed82c0c57d6e1e3408e84ac449ab8e94,ad7eff07b625f53c3fb513b30d7a8c5a79fbc7ce)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[c6307674ed82c0c57d6e1e3408e84ac449ab8e94,04aa71da5f35aacdc9ae9cb5150947daa624f641)"}}], "enrichment": {"confidence": 99.0, "confidence_source": "inferred", "scores": [{"score": 99.0, "source": "inferred"}, {"score": 100.0, "source": "matching"}]}, "original": {"product": "Linux", "source": "cna", "vendor": "Linux"}, "product": "linux_kernel", "vendor": "linux"}, {"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "generic", "value": "6.19"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[0,6.19)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[7.0.12,7.1.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[7.1,*]"}}], "enrichment": {"confidence": 99.0, "confidence_source": "inferred", "scores": [{"score": 99.0, "source": "inferred"}, {"score": 100.0, "source": "matching"}]}, "original": {"product": "Linux", "source": "cna", "vendor": "Linux"}, "product": "linux_kernel", "vendor": "linux"}], "created": "2026-07-21T11:30:06.116090+00:00", "updated": "2026-10-30T17:45:15.036293+00:00", "vendors": ["linux", "linux$PRODUCT$linux_kernel"]}