{"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"}}}}