{"id":"CVE-2026-121405","kind":"vulnerability","aliases":["CVE-2026-121405"],"related":[],"title":"FreeRDP: unbounded serial IRP buffer lets a malicious server exhaust client memory","description":"FreeRDP before 3.32.2 fails to cap the OutputBufferLength in serial device-control IRP requests, allowing malicious servers to trigger excessive memory allocation. Attackers running a server with serial redirection can send an IRP_MJ_DEVICE_CONTROL request with IOCTL_USBPRINT_GET_1284_ID and a near-maximum length to exhaust client memory.","summary":"FreeRDP before 3.32.2 does not cap the OutputBufferLength in serial device-control IRP requests. A malicious RDP server with serial redirection can make the client allocate excessive memory, exhausting it.","severity":"medium","cvss":5.3,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["freerdp","linux","package","rdp-clients","windows"],"not_affected_if":["fixed-version","no-serial-redirection","trusted-servers-only"],"how_to_check":"- Check the installed FreeRDP version, for example `xfreerdp /version`, and compare it with the fixed version.\n- Look for serial port redirection enabled in RDP client sessions (unknown exact setting name in sources).","fix":"- FreeRDP: upgrade to `3.32.2` or later.","status":"open","published_at":"2026-11-03T15:17:29+00:00","first_seen_at":"2026-11-03T15:21:58+00:00","triaged_at":"2026-11-03T15:24:29+00:00","updated_at":"2026-11-03T15:24:29+00:00","category":"package","confidence":0.7,"triage":{"at":"2026-11-03T15:24:29Z","model":"claude-haiku-5-5","output":{"fix":"- FreeRDP: upgrade to `3.32.2` or later.","reach":"network","title":"FreeRDP: unbounded serial IRP buffer lets a malicious server exhaust client memory","impact":"low","summary":"FreeRDP before 3.32.2 does not cap the OutputBufferLength in serial device-control IRP requests. A malicious RDP server with serial redirection can make the client allocate excessive memory, exhausting it.","audience":"developers","category":"package","nicknames":[],"who_cares":["freerdp","rdp-clients","linux","windows"],"confidence":0.7,"fix_status":"available","needs_auth":"no","worst_case":"malicious server exhausts client memory, causing crash or denial of service","analyst_note":"","how_to_check":"- Check the installed FreeRDP version, for example `xfreerdp /version`, and compare it with the fixed version.\n- Look for serial port redirection enabled in RDP client sessions (unknown exact setting name in sources).","plain_action":"","needs_analyst":false,"not_affected_if":["fixed-version","no-serial-redirection","trusted-servers-only"],"who_is_affected":"Teams that build or ship the FreeRDP client, or run it to connect to RDP servers they do not fully trust. Exposure requires the server to use serial redirection; the sources do not say whether it is off by default. Teams connecting only to their own trusted servers can deprioritize.","user_interaction":"unknown","needs_special_setup":"yes","severity_if_unknown":"medium"},"cost_usd":0.000687,"input_tokens":4210,"output_tokens":533,"severity_before":"medium"},"analyst_status":null,"analyst_note":null,"search":"'-121405':15A,18A '-2026':14A,17A '1284':98C '3.32.2':28B,58C 'alloc':52B,78C 'allow':71C 'attack':79C 'buffer':5A 'cap':31B,61C 'client':11A,24B,51B,108C 'control':38B,68C,92C 'cve':13A,16A 'devic':37B,67C,91C 'device-control':36B,66C 'excess':53B,76C 'exhaust':10A,55B,107C 'fail':59C 'freerdp':1A,19B,26B,56C 'get':97C 'id':99C 'ioctl':95C 'irp':4A,39B,69C,89C 'length':105C 'let':6A 'linux':20B 'make':49B 'malici':8A,42B,72C 'maximum':104C 'memori':12A,54B,77C,109C 'mj':90C 'near':103C 'near-maximum':102C 'outputbufferlength':33B,63C 'packag':21B 'rdp':23B,43B 'rdp-client':22B 'redirect':47B,85C 'request':40B,70C,93C 'run':80C 'send':87C 'serial':3A,35B,46B,65C,84C 'server':9A,44B,73C,82C 'trigger':75C 'unbound':2A 'usbprint':96C 'window':25B","nicknames":[],"mitigations":[],"who_affected":"Teams that build or ship the FreeRDP client, or run it to connect to RDP servers they do not fully trust. Exposure requires the server to use serial redirection; the sources do not say whether it is off by default. Teams connecting only to their own trusted servers can deprioritize.","tier":"C","verified":{},"analyst_revisit_at":null,"fix_status":"available","audience":"developers","plain_action":null,"pkeys":[],"ptokens":[],"labels":["freerdp","linux","medium","package","rdpclients","windows"],"first_public_at":"2026-10-19T12:05:43+00:00","kev":null,"cvss_vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/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":"disclosure@vulncheck.com","poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-121405","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-121405","severity":null,"published_at":"2026-11-03T15:17:29+00:00","modified_at":"2026-11-03T15:17:29+00:00","first_seen_at":"2026-11-03T15:21:58+00:00","fetched_at":"2026-11-03T15:21:58+00:00","note":null}],"documents":[{"id":58333,"url":"https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-r387-jjq3-87hv","title":"Vendor advisory: github.com","kind":"vendor","source":"nvd","publisher":"vendor","text":null,"published_at":"2026-10-19T12:05:43+00:00","relation":"advisory","confidence":null,"note":"Vendor advisory: github.com"},{"id":58334,"url":"https://www.vulncheck.com/advisories/freerdp-before-3.32.2-memory-exhaustion-via-serial-rdpdr-device-control","title":"Third-party advisory: www.vulncheck.com","kind":"advisory","source":"nvd","publisher":"research","text":null,"published_at":null,"relation":"advisory","confidence":null,"note":"Third-party advisory: www.vulncheck.com"}],"notice":"Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai"}