{"id":"CVE-2026-56946","kind":"vulnerability","aliases":["CVE-2026-56946"],"related":[],"title":"Linux kernel ARM SMMU: unmapping bug lets local users escalate privileges","description":"In smmu_unmap_visit_leaf of arm-smmu-v3.c, there is a possible way to release active direct memory access page references during unmapping due to a logic error. This could lead to local escalation of privilege with System execution privileges needed. User interaction is not needed for exploitation.","summary":"A logic error in the Arm SMMUv3 driver (smmu_unmap_visit_leaf in arm-smmu-v3.c) can release DMA page references that are still active during unmapping. A local attacker with system-level execution can use this to escalate privileges.","severity":"unknown","cvss":null,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["arm64","infrastructure","iommu","linux-kernel","servers"],"not_affected_if":["no-arm-smmuv3-hardware"],"how_to_check":null,"fix":null,"status":"open","published_at":"2026-11-10T20:19:16+00:00","first_seen_at":"2026-11-10T20:46:07+00:00","triaged_at":"2026-11-10T20:52:20+00:00","updated_at":"2026-11-10T20:52:20+00:00","category":"infrastructure","confidence":0.5,"triage":{"at":"2026-11-10T20:52:20Z","model":"claude-haiku-5-5","output":{"fix":"unknown","reach":"local","title":"Linux kernel ARM SMMU: unmapping bug lets local users escalate privileges","impact":"high","summary":"A logic error in the Arm SMMUv3 driver (smmu_unmap_visit_leaf in arm-smmu-v3.c) can release DMA page references that are still active during unmapping. A local attacker with system-level execution can use this to escalate privileges.","audience":"businesses","category":"infrastructure","nicknames":[],"who_cares":["linux-kernel","arm64","iommu","servers"],"confidence":0.5,"fix_status":"unknown","needs_auth":"yes","worst_case":"local user escalates to kernel-level privileges on the host","analyst_note":"Find affected and fixed kernel versions for CVE-2026-56946 in the Linux kernel stable trees or the NVD entry, and confirm whether the flaw is limited to Arm SMMUv3 configurations.","how_to_check":"- unknown","plain_action":"","product_name":"","needs_analyst":true,"not_affected_if":["no-arm-smmuv3-hardware"],"who_is_affected":"Systems with an Arm SMMUv3 IOMMU and its arm-smmu-v3 driver loaded are the ones in scope; the sources do not list affected kernel versions. Machines without Arm SMMUv3 hardware are unlikely to be exposed. unknown for the exact affected ranges.","user_interaction":"no","product_ecosystem":"","needs_special_setup":"yes","severity_if_unknown":"high"},"cost_usd":0.000718,"input_tokens":4545,"output_tokens":528,"severity_before":"unknown"},"analyst_status":null,"analyst_note":null,"search":"'-2026':13A,16A '-56946':14A,17A 'access':89C 'activ':51B,86C 'arm':3A,30B,39B,75C 'arm-smmu-v3':38B,74C 'arm64':18B 'attack':56B 'bug':6A 'c':42B,78C 'could':100C 'cve':12A,15A 'direct':87C 'dma':45B 'driver':32B 'due':94C 'error':27B,98C 'escal':10A,66B,104C 'execut':61B,109C 'exploit':118C 'infrastructur':19B 'interact':113C 'iommu':20B 'kernel':2A,23B 'lead':101C 'leaf':36B,72C 'let':7A 'level':60B 'linux':1A,22B 'linux-kernel':21B 'local':8A,55B,103C 'logic':26B,97C 'memori':88C 'need':111C,116C 'page':46B,90C 'possibl':82C 'privileg':11A,67B,106C,110C 'refer':47B,91C 'releas':44B,85C 'server':24B 'smmu':4A,33B,40B,69C,76C 'smmuv3':31B 'still':50B 'system':59B,108C 'system-level':58B 'unmap':5A,34B,53B,70C,93C 'use':63B 'user':9A,112C 'v3':41B,77C 'visit':35B,71C 'way':83C","nicknames":[],"mitigations":[],"who_affected":"Systems with an Arm SMMUv3 IOMMU and its arm-smmu-v3 driver loaded are the ones in scope; the sources do not list affected kernel versions. Machines without Arm SMMUv3 hardware are unlikely to be exposed. unknown for the exact affected ranges.","tier":"C","verified":{},"analyst_revisit_at":null,"fix_status":"none","audience":"businesses","plain_action":null,"pkeys":[],"ptokens":[],"labels":["arm64","infrastructure","iommu","linuxkernel","servers","unknown"],"campaign_type":null,"search_a":"'-2026':13A,16A '-56946':14A,17A 'arm':3A 'bug':6A 'cve':12A,15A 'escal':10A 'kernel':2A 'let':7A 'linux':1A 'local':8A 'privileg':11A 'smmu':4A 'unmap':5A 'user':9A","search_b":"'activ':51B 'arm':30B,39B 'arm-smmu-v3':38B 'arm64':18B 'attack':56B 'c':42B 'dma':45B 'driver':32B 'error':27B 'escal':66B 'execut':61B 'infrastructur':19B 'iommu':20B 'kernel':23B 'leaf':36B 'level':60B 'linux':22B 'linux-kernel':21B 'local':55B 'logic':26B 'page':46B 'privileg':67B 'refer':47B 'releas':44B 'server':24B 'smmu':33B,40B 'smmuv3':31B 'still':50B 'system':59B 'system-level':58B 'unmap':34B,53B 'use':63B 'v3':41B 'visit':35B","search_c":"'access':89C 'activ':86C 'arm':75C 'arm-smmu-v3':74C 'c':78C 'could':100C 'direct':87C 'due':94C 'error':98C 'escal':104C 'execut':109C 'exploit':118C 'interact':113C 'lead':101C 'leaf':72C 'local':103C 'logic':97C 'memori':88C 'need':111C,116C 'page':90C 'possibl':82C 'privileg':106C,110C 'refer':91C 'releas':85C 'smmu':69C,76C 'system':108C 'unmap':70C,93C 'user':112C 'v3':77C 'visit':71C 'way':83C","cause_entry":null,"cause_path":null,"disclosures_checked_at":null,"first_public_at":"2026-11-10T20:19:16+00:00","kev":null,"cvss_vector":null,"cvss_by":null,"poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-56946","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-56946","severity":null,"published_at":"2026-11-10T20:19:16+00:00","modified_at":"2026-11-10T20:19:16+00:00","first_seen_at":"2026-11-10T20:46:07+00:00","fetched_at":"2026-11-10T20:46:07+00:00","note":null}],"documents":[],"disclosures":[],"exploit_sources":[],"notice":"Free to read, with fair use of about 60 pages a minute. For higher limits or API access: sales@infrastack.ai"}