{"id":"CVE-2026-20546","kind":"vulnerability","aliases":["CVE-2026-20546"],"related":[],"title":"Modem firmware: out-of-bounds write lets a rogue base station take over","description":"In Modem, there is a possible out of bounds write due to an incorrect bounds check. This could lead to remote escalation of privilege, if a UE has connected to a rogue base station controlled by the attacker, with no additional execution privileges needed. User interaction is not needed for exploitation. Patch ID: MOLY01876654 / MOLY01774038; Issue ID: MSV-9803.","summary":"A bounds-check flaw in the modem firmware allows an out-of-bounds write that can escalate privileges remotely. An attacker running a rogue base station can trigger it when a phone or device connects to it, with no user interaction needed.","severity":"unknown","cvss":null,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["cellular","infrastructure","mobile-devices","modem"],"not_affected_if":["no-cellular-modem"],"how_to_check":null,"fix":null,"status":"open","published_at":"2026-11-02T03:17:31+00:00","first_seen_at":"2026-11-02T03:31:24+00:00","triaged_at":"2026-11-02T03:33:58+00:00","updated_at":"2026-11-02T03:33:58+00:00","category":"infrastructure","confidence":0.5,"triage":{"at":"2026-11-02T03:33:58Z","model":"claude-haiku-5-5","output":{"fix":"- unknown","reach":"network","title":"Modem firmware: out-of-bounds write lets a rogue base station take over","impact":"high","summary":"A bounds-check flaw in the modem firmware allows an out-of-bounds write that can escalate privileges remotely. An attacker running a rogue base station can trigger it when a phone or device connects to it, with no user interaction needed.","audience":"everyone","category":"infrastructure","nicknames":[],"who_cares":["modem","cellular","mobile-devices"],"confidence":0.5,"fix_status":"unknown","needs_auth":"no","worst_case":"Attacker gains escalated privileges on the modem via a rogue base station","analyst_note":"Identify which device vendors and firmware builds ship MOLY01876654 / MOLY01774038 and confirm the fixed versions; the NVD entry gives no product or version ranges.","how_to_check":"- unknown","plain_action":"Update your phone or device to the latest software from its maker once the security update is released.","needs_analyst":true,"not_affected_if":["no-cellular-modem"],"who_is_affected":"Devices with the affected modem firmware that connect to cellular networks can be exposed to a rogue base station. The sources do not name the affected devices or firmware versions. Systems that never use cellular connectivity are not affected.","user_interaction":"no","needs_special_setup":"unknown","severity_if_unknown":"high"},"cost_usd":0.000659,"input_tokens":4135,"output_tokens":491,"severity_before":"unknown"},"analyst_status":null,"analyst_note":null,"search":"'-2026':15A,18A '-20546':16A,19A '-9803':128C 'addit':110C 'allow':35B 'attack':48B,107C 'base':11A,52B,102C 'bound':6A,28B,40B,78C,84C 'bounds-check':27B 'cellular':20B 'check':29B,85C 'connect':62B,98C 'control':104C 'could':87C 'cve':14A,17A 'devic':24B,61B 'due':80C 'escal':44B,91C 'execut':111C 'exploit':120C 'firmwar':2A,34B 'flaw':30B 'id':122C,126C 'incorrect':83C 'infrastructur':21B 'interact':68B,115C 'issu':125C 'lead':88C 'let':8A 'mobil':23B 'mobile-devic':22B 'modem':1A,25B,33B,71C 'moly01774038':124C 'moly01876654':123C 'msv':127C 'need':69B,113C,118C 'out-of-bound':3A,37B 'patch':121C 'phone':59B 'possibl':75C 'privileg':45B,93C,112C 'remot':46B,90C 'rogu':10A,51B,101C 'run':49B 'station':12A,53B,103C 'take':13A 'trigger':55B 'ue':96C 'user':67B,114C 'write':7A,41B,79C","nicknames":[],"mitigations":[],"who_affected":"Devices with the affected modem firmware that connect to cellular networks can be exposed to a rogue base station. The sources do not name the affected devices or firmware versions. Systems that never use cellular connectivity are not affected.","tier":"C","verified":{},"analyst_revisit_at":null,"fix_status":"unknown","audience":"everyone","plain_action":null,"pkeys":[],"ptokens":[],"labels":["cellular","infrastructure","mobiledevices","modem","unknown"],"first_public_at":"2026-11-02T03:17:31+00:00","kev":null,"cvss_vector":null,"cvss_by":null,"poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-20546","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-20546","severity":null,"published_at":"2026-11-02T03:17:31+00:00","modified_at":"2026-11-02T03:17:31+00:00","first_seen_at":"2026-11-02T03:31:24+00:00","fetched_at":"2026-11-02T03:31:24+00:00","note":null}],"documents":[],"notice":"Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai"}