{"id":"CVE-2026-20557","kind":"vulnerability","aliases":["CVE-2026-20557"],"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 a missing 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: MOLY01877236; Issue ID: MSV-9804.","summary":"A missing bounds check in the modem firmware allows an out-of-bounds write. A phone or device that connects to an attacker-controlled rogue base station can be pushed to escalate privileges remotely, with no user interaction.","severity":"unknown","cvss":null,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["android","infrastructure","mobile","modem"],"not_affected_if":["no-cellular-modem"],"how_to_check":null,"fix":null,"status":"open","published_at":"2026-11-02T03:17:32+00:00","first_seen_at":"2026-11-02T03:31:24+00:00","triaged_at":"2026-11-02T03:32:36+00:00","updated_at":"2026-11-02T03:32:36+00:00","category":"infrastructure","confidence":0.4,"triage":{"at":"2026-11-02T03:32:36Z","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 missing bounds check in the modem firmware allows an out-of-bounds write. A phone or device that connects to an attacker-controlled rogue base station can be pushed to escalate privileges remotely, with no user interaction.","audience":"everyone","category":"infrastructure","nicknames":[],"who_cares":["modem","mobile","android"],"confidence":0.4,"fix_status":"unknown","needs_auth":"no","worst_case":"Remote privilege escalation on a device that joins a rogue tower","analyst_note":"Identify the affected devices and vendor advisory for Patch ID MOLY01877236 / MSV-9804 and the fixed firmware version; the NVD entry alone does not name products.","how_to_check":"- unknown","plain_action":"Update your phone to the latest software from its maker once a security update covering this modem flaw is released.","needs_analyst":true,"not_affected_if":["no-cellular-modem"],"who_is_affected":"Devices with a cellular modem that can connect to a fake base station (IMSI-catcher style rogue tower) are the exposed set. The sources name only the Modem component and a Patch ID (MOLY01877236), not affected product versions. unknown for which devices or chipsets are affected.","user_interaction":"no","needs_special_setup":"no","severity_if_unknown":"high"},"cost_usd":0.000665,"input_tokens":4122,"output_tokens":505,"severity_before":"unknown"},"analyst_status":null,"analyst_note":null,"search":"'-2026':15A,18A '-20557':16A,19A '-9804':121C 'addit':104C 'allow':32B 'android':20B 'attack':48B,101C 'attacker-control':47B 'base':11A,51B,96C 'bound':6A,26B,37B,72C,78C 'check':27B,79C 'connect':44B,92C 'control':49B,98C 'could':81C 'cve':14A,17A 'devic':42B 'due':74C 'escal':57B,85C 'execut':105C 'exploit':114C 'firmwar':2A,31B 'id':116C,119C 'infrastructur':21B 'interact':63B,109C 'issu':118C 'lead':82C 'let':8A 'miss':25B,77C 'mobil':22B 'modem':1A,23B,30B,65C 'moly01877236':117C 'msv':120C 'need':107C,112C 'out-of-bound':3A,34B 'patch':115C 'phone':40B 'possibl':69C 'privileg':58B,87C,106C 'push':55B 'remot':59B,84C 'rogu':10A,50B,95C 'station':12A,52B,97C 'take':13A 'ue':90C 'user':62B,108C 'write':7A,38B,73C","nicknames":[],"mitigations":[],"who_affected":"Devices with a cellular modem that can connect to a fake base station (IMSI-catcher style rogue tower) are the exposed set. The sources name only the Modem component and a Patch ID (MOLY01877236), not affected product versions. unknown for which devices or chipsets are affected.","tier":"C","verified":{},"analyst_revisit_at":null,"fix_status":"unknown","audience":"everyone","plain_action":null,"pkeys":[],"ptokens":[],"labels":["android","infrastructure","mobile","modem","unknown"],"first_public_at":"2026-11-02T03:17:32+00:00","kev":null,"cvss_vector":null,"cvss_by":null,"poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-20557","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-20557","severity":null,"published_at":"2026-11-02T03:17:32+00:00","modified_at":"2026-11-02T03:17:32+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"}