{"id":"CVE-2026-41221","kind":"vulnerability","aliases":["CVE-2026-41221"],"related":[],"title":"Intel Slim Bootloader UEFI firmware integer overflow allows privilege escalation","description":"Integer 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":"An integer overflow in the UEFI firmware of Intel's Slim Bootloader lets code running at firmware or System Management Mode level escalate privileges on the machine. The sources say an attacker with physical access and low complexity could gain full control of confidentiality, integrity and availability.","severity":"high","cvss":8.6,"epss":null,"exploited":false,"exploited_at":null,"products":[{"name":"slim-bootloader","fixed":["commit 9e77d9abb867e7ab4fec8249035cf9ba6550aed7 or later"],"affected":"builds before commit 9e77d9abb867e7ab4fec8249035cf9ba6550aed7 (July 7th, 2026)","ecosystem":"vendor"}],"ecosystems":[],"tags":["bare-metal","embedded","infrastructure","intel","physical-access","slim-bootloader","uefi-firmware"],"not_affected_if":["no-physical-access","not-slim-bootloader","unknown"],"how_to_check":"Find the Slim Bootloader commit/build your device firmware was built from (ask your board or device vendor, or check the SBL build info) and see whether it predates commit 9e77d9abb867e7ab4fec8249035cf9ba6550aed7 (July 7th, 2026). Intel lists platforms: 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, Raptor Lake, Tiger Lake. Only devices actually booting Slim Bootloader matter.","fix":"Update Intel Slim Bootloader to the build at commit hash 9e77d9abb867e7ab4fec8249035cf9ba6550aed7 (from July 7th, 2026) or later; firmware updates come through your board/device vendor.","status":"open","published_at":"2026-11-10T18:17:38+00:00","first_seen_at":"2026-11-10T18:22:57+00:00","triaged_at":"2026-11-10T18:24:22+00:00","updated_at":"2026-11-10T18:29:01+00:00","category":"infrastructure","confidence":0.85,"triage":{"at":"2026-11-10T18:24:22Z","model":"claude-haiku-5-5","output":{"fix":"unknown","reach":"local","title":"Intel Slim Bootloader UEFI firmware integer overflow allows privilege escalation","impact":"high","summary":"An integer overflow in the UEFI firmware of Intel's Slim Bootloader lets code running at firmware or System Management Mode level escalate privileges on the machine. The sources say an attacker with physical access and low complexity could gain full control of confidentiality, integrity and availability.","audience":"businesses","category":"infrastructure","nicknames":[],"who_cares":["intel","slim-bootloader","uefi-firmware","bare-metal"],"confidence":0.5,"fix_status":"unknown","needs_auth":"unknown","worst_case":"attacker gains full control of the system through firmware","analyst_note":"Find the Intel security advisory and the affected Slim Bootloader versions and fixed release, since the sources give no product ranges or fix.","how_to_check":"unknown","plain_action":"","product_name":"","needs_analyst":true,"not_affected_if":["unknown"],"who_is_affected":"Systems that boot with Intel's Slim Bootloader UEFI firmware are the ones exposed; the sources do not name affected versions or configurations. Teams running standard vendor-shipped firmware on ordinary PCs and servers are not indicated by the sources as affected.","user_interaction":"no","product_ecosystem":"","needs_special_setup":"unknown","severity_if_unknown":"high"},"cost_usd":0.000713,"input_tokens":4676,"output_tokens":490,"severity_before":"high"},"analyst_status":"done","analyst_note":"Find the Intel security advisory and the affected Slim Bootloader versions and fixed release, since the sources give no product ranges or fix.","search":"'-2026':12A,15A '-41221':13A,16A '0':96C 'access':28B,69B,133C 'adversari':110C 'allow':8A,101C 'attack':66B,120C,135C 'avail':81B,160C,175C 'bare':21B,97C 'bare-met':20B 'bootload':3A,31B,46B,93C 'bootloader':19A 'code':48B,107C 'combin':115C 'complex':72B,119C 'confidenti':78B,155C,170C 'control':76B 'could':73B 'cve':11A,14A 'embed':23B 'enabl':122C 'escal':10A,57B,103C,123C 'firmwar':5A,34B,41B,51B,87C 'full':75B 'gain':74B 'high':156C,158C,161C,171C,173C,176C 'impact':153C,177C 'infrastructur':24B 'integ':6A,36B,82C 'integr':79B,157C,172C 'intel':1A,25B,43B,90C 'interact':148C 'intern':142C 'knowledg':143C 'let':47B 'level':56B 'low':71B,118C 'machin':61B 'manag':54B 'may':100C,121C,128C,152C 'metal':22B,98C 'mode':55B 'occur':130C 'os':99C 'overflow':7A,37B,83C 'physic':27B,68B,132C 'physical-access':26B 'potenti':129C,150C 'present':139C 'privileg':9A,58B,105C,125C 'r':91C 'requir':136C,145C 'result':127C,166C 'ring':95C 'run':49B 'say':64B 'slim':2A,18A,30B,45B,92C 'slim-bootload':29B 'slim-bootloader':17A 'smm':109C 'sourc':63B 'special':141C 'startup':106C 'subsequ':168C 'system':53B,165C,169C 'uefi':4A,33B,40B,86C 'uefi-firmwar':32B 'unauthent':113C 'user':114C,147C 'via':131C 'vulner':151C,164C 'within':94C 'without':140C","nicknames":[],"mitigations":[],"who_affected":"Embedded and bare-metal devices that boot with Intel Slim Bootloader on the Intel platforms listed in INTEL-SA-01526 (Alder Lake, Apollo Lake, Elkhart Lake, Tiger Lake, Meteor Lake, Panther Lake and others). Exploitation needs physical access and startup-code/SMM-level adversary per Intel. Ordinary PCs with vendor UEFI (not Slim Bootloader) can skip it.","tier":"B","verified":{"fix":{"at":"2026-11-10T18:29:01Z","by":"analyst","doc":"https://www.intel.com/content/www/us/en/security-center/advisory/intel-sa-01526.html","run_id":2500},"products":{"at":"2026-11-10T18:29:01Z","by":"analyst","doc":"https://www.intel.com/content/www/us/en/security-center/advisory/intel-sa-01526.html","run_id":2500},"how_to_check":{"at":"2026-11-10T18:29:01Z","by":"analyst","doc":"https://www.intel.com/content/www/us/en/security-center/advisory/intel-sa-01526.html","run_id":2500},"who_affected":{"at":"2026-11-10T18:29:01Z","by":"analyst","doc":"https://www.intel.com/content/www/us/en/security-center/advisory/intel-sa-01526.html","run_id":2500}},"analyst_revisit_at":null,"fix_status":"available","audience":"businesses","plain_action":null,"pkeys":["slimbootloader"],"ptokens":["bootloader","slim"],"labels":["baremetal","embedded","high","infrastructure","intel","physicalaccess","slimbootloader","uefifirmware"],"campaign_type":null,"search_a":"'-2026':12A,15A '-41221':13A,16A 'allow':8A 'bootload':3A 'bootloader':19A 'cve':11A,14A 'escal':10A 'firmwar':5A 'integ':6A 'intel':1A 'overflow':7A 'privileg':9A 'slim':2A,18A 'slim-bootloader':17A 'uefi':4A","search_b":"'access':28B,69B 'attack':66B 'avail':81B 'bare':21B 'bare-met':20B 'bootload':31B,46B 'code':48B 'complex':72B 'confidenti':78B 'control':76B 'could':73B 'embed':23B 'escal':57B 'firmwar':34B,41B,51B 'full':75B 'gain':74B 'infrastructur':24B 'integ':36B 'integr':79B 'intel':25B,43B 'let':47B 'level':56B 'low':71B 'machin':61B 'manag':54B 'metal':22B 'mode':55B 'overflow':37B 'physic':27B,68B 'physical-access':26B 'privileg':58B 'run':49B 'say':64B 'slim':30B,45B 'slim-bootload':29B 'sourc':63B 'system':53B 'uefi':33B,40B 'uefi-firmwar':32B","search_c":"'0':96C 'access':133C 'adversari':110C 'allow':101C 'attack':120C,135C 'avail':160C,175C 'bare':97C 'bootload':93C 'code':107C 'combin':115C 'complex':119C 'confidenti':155C,170C 'enabl':122C 'escal':103C,123C 'firmwar':87C 'high':156C,158C,161C,171C,173C,176C 'impact':153C,177C 'integ':82C 'integr':157C,172C 'intel':90C 'interact':148C 'intern':142C 'knowledg':143C 'low':118C 'may':100C,121C,128C,152C 'metal':98C 'occur':130C 'os':99C 'overflow':83C 'physic':132C 'potenti':129C,150C 'present':139C 'privileg':105C,125C 'r':91C 'requir':136C,145C 'result':127C,166C 'ring':95C 'slim':92C 'smm':109C 'special':141C 'startup':106C 'subsequ':168C 'system':165C,169C 'uefi':86C 'unauthent':113C 'user':114C,147C 'via':131C 'vulner':151C,164C 'within':94C 'without':140C","cause_entry":null,"cause_path":null,"disclosures_checked_at":null,"first_public_at":"2026-11-10T18:17:38+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-2026-41221","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-41221","severity":null,"published_at":"2026-11-10T18:17:38+00:00","modified_at":"2026-11-10T18:17:38+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-2026-41221:2500","url":"https://www.intel.com/content/www/us/en/security-center/advisory/intel-sa-01526.html","severity":null,"published_at":"2026-11-10T18:29:01+00:00","modified_at":"2026-11-10T18:29:01+00:00","first_seen_at":"2026-11-10T18:29:01+00:00","fetched_at":"2026-11-10T18:29:01+00:00","note":"Found Intel INTEL-SA-01526 (11/10/2026, also CVE-2026-35500/41224/50175/44624/28746). Fix is a commit hash, no version numbers; affected list is by processor platform.","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"}