{"id":"CVE-2026-35500","kind":"vulnerability","aliases":["CVE-2026-35500"],"related":[],"title":"Intel Slim Bootloader UEFI firmware: stack overflow allows privilege escalation","description":"Stack-based buffer overflow in the UEFI firmware for the Intel(R) Slim Bootloader within Ring 0: Bare Metal OS may allow an escalation of privilege. Startup code and smm adversary with an unauthenticated user combined with a low complexity attack may enable escalation of privilege. This result may potentially occur via physical access when attack requirements are not present without special internal knowledge and requires no user interaction. The potential vulnerability may impact the confidentiality (high), integrity (high) and availability (high) of the vulnerable system, resulting in subsequent system confidentiality (high), integrity (high) and availability (high) impacts.","summary":"A stack-based buffer overflow in the UEFI firmware of Intel's Slim Bootloader lets an attacker with low privileges escalate to Ring 0 on bare-metal systems. The sources describe full confidentiality, integrity and availability impact, and the attack is reported as possible with physical access.","severity":"high","cvss":8.6,"epss":null,"exploited":false,"exploited_at":null,"products":[{"name":"Intel Slim Bootloader","fixed":["9e77d9abb867e7ab4fec8249035cf9ba6550aed7"],"affected":"builds older than commit 9e77d9abb867e7ab4fec8249035cf9ba6550aed7 (July 7, 2026)","ecosystem":"vendor"}],"ecosystems":[],"tags":["bare-metal","embedded","infrastructure","intel","physical-access","slim-bootloader","uefi-firmware"],"not_affected_if":["other-firmware","physical-access-controlled"],"how_to_check":"Find out whether your device boots Intel Slim Bootloader (common on embedded/IoT/edge boards) and on one of the CPUs in INTEL-SA-01526 (Alder Lake, Twin Lake, Apollo Lake, Arrow Lake, Bartlett Lake-S, Coffee Lake, Comet Lake, Elkhart Lake, Ice Lake-D, Granite Rapids-D, Meteor Lake, Panther Lake, Tiger Lake, 13th gen). Compare your SBL build against hash 9e77d9ab... (July 7, 2026); older means exposed. Intel gives no command; ask your board vendor.","fix":"Update Intel Slim Bootloader to the build at commit hash 9e77d9abb867e7ab4fec8249035cf9ba6550aed7 (July 7th, 2026) or later; get firmware from your device/board vendor.","status":"open","published_at":"2026-11-10T18:17:37+00:00","first_seen_at":"2026-11-10T18:22:57+00:00","triaged_at":"2026-11-10T18:24:23+00:00","updated_at":"2026-11-10T18:29:04+00:00","category":"infrastructure","confidence":0.85,"triage":{"at":"2026-11-10T18:24:23Z","model":"claude-haiku-5-5","output":{"fix":"unknown","reach":"local","title":"Intel Slim Bootloader UEFI firmware: stack overflow allows privilege escalation","impact":"high","summary":"A stack-based buffer overflow in the UEFI firmware of Intel's Slim Bootloader lets an attacker with low privileges escalate to Ring 0 on bare-metal systems. The sources describe full confidentiality, integrity and availability impact, and the attack is reported as possible with physical access.","audience":"businesses","category":"infrastructure","nicknames":[],"who_cares":["intel","slim-bootloader","uefi-firmware","bare-metal"],"confidence":0.5,"fix_status":"unknown","needs_auth":"yes","worst_case":"attacker gains Ring 0 code execution and full system compromise","analyst_note":"Find Intel's advisory for CVE-2026-35500 to confirm affected firmware versions, fixed builds and whether physical access is the only vector.","how_to_check":"unknown","plain_action":"","product_name":"","needs_analyst":true,"not_affected_if":["other-firmware"],"who_is_affected":"Systems that boot Intel Slim Bootloader UEFI firmware are the ones exposed; the sources do not list affected versions or whether a default configuration is vulnerable. Teams running standard x86 servers or laptops with other firmware are unlikely to be affected, but the sources do not confirm this.","user_interaction":"no","product_ecosystem":"","needs_special_setup":"unknown","severity_if_unknown":"unknown"},"cost_usd":0.000729,"input_tokens":4683,"output_tokens":522,"severity_before":"high"},"analyst_status":"done","analyst_note":"Find Intel's advisory for CVE-2026-35500 to confirm affected firmware versions, fixed builds and whether physical access is the only vector.","search":"'-2026':12A,15A '-35500':13A,16A '0':59B,101C 'access':28B,83B,138C 'adversari':115C 'allow':8A,106C 'attack':52B,76B,125C,140C 'avail':72B,165C,180C 'bare':21B,62B,102C 'bare-met':20B,61B 'base':38B,86C 'bootload':3A,31B,49B,98C 'bootloader':19A 'buffer':39B,87C 'code':112C 'combin':120C 'complex':124C 'confidenti':69B,160C,175C 'cve':11A,14A 'describ':67B 'embed':23B 'enabl':127C 'escal':10A,56B,108C,128C 'firmwar':5A,34B,44B,92C 'full':68B 'high':161C,163C,166C,176C,178C,181C 'impact':73B,158C,182C 'infrastructur':24B 'integr':70B,162C,177C 'intel':1A,17A,25B,46B,95C 'interact':153C 'intern':147C 'knowledg':148C 'let':50B 'low':54B,123C 'may':105C,126C,133C,157C 'metal':22B,63B,103C 'occur':135C 'os':104C 'overflow':7A,40B,88C 'physic':27B,82B,137C 'physical-access':26B 'possibl':80B 'potenti':134C,155C 'present':144C 'privileg':9A,55B,110C,130C 'r':96C 'report':78B 'requir':141C,150C 'result':132C,171C 'ring':58B,100C 'slim':2A,18A,30B,48B,97C 'slim-bootload':29B 'smm':114C 'sourc':66B 'special':146C 'stack':6A,37B,85C 'stack-bas':36B,84C 'startup':111C 'subsequ':173C 'system':64B,170C,174C 'uefi':4A,33B,43B,91C 'uefi-firmwar':32B 'unauthent':118C 'user':119C,152C 'via':136C 'vulner':156C,169C 'within':99C 'without':145C","nicknames":[],"mitigations":[],"who_affected":"Devices that boot Intel Slim Bootloader on the Intel processors listed in INTEL-SA-01526 are affected. Intel rates the attack as physical-access only (CVSS 4.0 AV:P, no privileges, no user interaction), so the risk is mainly for unattended edge, embedded or kiosk hardware. Systems using other firmware (standard UEFI/BIOS, coreboot) can skip it. Intel says it was found internally; no exploitation reported.","tier":"B","verified":{"fix":{"at":"2026-11-10T18:29:04Z","by":"analyst","doc":"https://www.intel.com/content/www/us/en/security-center/advisory/intel-sa-01526.html","run_id":2502},"products":{"at":"2026-11-10T18:29:04Z","by":"analyst","doc":"https://www.intel.com/content/www/us/en/security-center/advisory/intel-sa-01526.html","run_id":2502},"who_affected":{"at":"2026-11-10T18:29:04Z","by":"analyst","doc":"https://www.intel.com/content/www/us/en/security-center/advisory/intel-sa-01526.html","run_id":2502}},"analyst_revisit_at":null,"fix_status":"available","audience":"businesses","plain_action":null,"pkeys":["intelslimbootloader","slimbootloader"],"ptokens":["bootloader","intel","slim"],"labels":["baremetal","embedded","high","infrastructure","intel","physicalaccess","slimbootloader","uefifirmware"],"campaign_type":null,"search_a":"'-2026':12A,15A '-35500':13A,16A 'allow':8A 'bootload':3A 'bootloader':19A 'cve':11A,14A 'escal':10A 'firmwar':5A 'intel':1A,17A 'overflow':7A 'privileg':9A 'slim':2A,18A 'stack':6A 'uefi':4A","search_b":"'0':59B 'access':28B,83B 'attack':52B,76B 'avail':72B 'bare':21B,62B 'bare-met':20B,61B 'base':38B 'bootload':31B,49B 'buffer':39B 'confidenti':69B 'describ':67B 'embed':23B 'escal':56B 'firmwar':34B,44B 'full':68B 'impact':73B 'infrastructur':24B 'integr':70B 'intel':25B,46B 'let':50B 'low':54B 'metal':22B,63B 'overflow':40B 'physic':27B,82B 'physical-access':26B 'possibl':80B 'privileg':55B 'report':78B 'ring':58B 'slim':30B,48B 'slim-bootload':29B 'sourc':66B 'stack':37B 'stack-bas':36B 'system':64B 'uefi':33B,43B 'uefi-firmwar':32B","search_c":"'0':101C 'access':138C 'adversari':115C 'allow':106C 'attack':125C,140C 'avail':165C,180C 'bare':102C 'base':86C 'bootload':98C 'buffer':87C 'code':112C 'combin':120C 'complex':124C 'confidenti':160C,175C 'enabl':127C 'escal':108C,128C 'firmwar':92C 'high':161C,163C,166C,176C,178C,181C 'impact':158C,182C 'integr':162C,177C 'intel':95C 'interact':153C 'intern':147C 'knowledg':148C 'low':123C 'may':105C,126C,133C,157C 'metal':103C 'occur':135C 'os':104C 'overflow':88C 'physic':137C 'potenti':134C,155C 'present':144C 'privileg':110C,130C 'r':96C 'requir':141C,150C 'result':132C,171C 'ring':100C 'slim':97C 'smm':114C 'special':146C 'stack':85C 'stack-bas':84C 'startup':111C 'subsequ':173C 'system':170C,174C 'uefi':91C 'unauthent':118C 'user':119C,152C 'via':136C 'vulner':156C,169C 'within':99C 'without':145C","cause_entry":null,"cause_path":null,"disclosures_checked_at":null,"first_public_at":"2026-11-10T18:17:37+00:00","kev":null,"cvss_vector":"CVSS:4.0/AV:P/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","cvss_by":"secure@intel.com","poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-35500","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-35500","severity":null,"published_at":"2026-11-10T18:17:37+00:00","modified_at":"2026-11-10T18:17:37+00:00","first_seen_at":"2026-11-10T18:22:57+00:00","fetched_at":"2026-11-10T18:22:57+00:00","note":null},{"source":"analyst","external_id":"CVE-2026-35500:2502","url":"https://www.intel.com/content/www/us/en/security-center/advisory/intel-sa-01526.html","severity":null,"published_at":"2026-11-10T18:29:04+00:00","modified_at":"2026-11-10T18:29:04+00:00","first_seen_at":"2026-11-10T18:29:04+00:00","fetched_at":"2026-11-10T18:29:04+00:00","note":"Intel INTEL-SA-01526 (released 2026-11-10) read: CVE-2026-35500 stack overflow in UEFI firmware, AV:P CVSS 8.6, found internally, fix = SBL hash 9e77d9ab from Jul 7 2026 or later. how_to_check is my wording, not verified. No exploitation or PoC seen; did not search social.","cites":["https://www.intel.com/content/www/us/en/security-center/advisory/intel-sa-01526.html"]}],"documents":[{"id":117070,"url":"https://www.intel.com/content/www/us/en/security-center/advisory/intel-sa-01526.html","title":"INTEL-SA-01526 Intel Slim Bootloader Advisory","kind":"advisory","source":"analyst","publisher":null,"text":null,"published_at":null,"relation":"advisory","confidence":null,"note":null}],"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"}