{"id":"CVE-2026-121951","kind":"vulnerability","aliases":["CVE-2026-121951"],"related":[],"title":"FreeRDP: malformed RDP input event crashes server, causing denial of service","description":"FreeRDP 3.0.0 before 3.32.2 server-side RDP peer input parsing skips the six-byte body of a slow-path input event with an unknown message type without checking it lies within the packet's declared length, causing a WinPR stream assertion failure. A remote RDP client with an active session can send a truncated unknown input event to abort assertion-enabled server processes, causing denial of service.","summary":"FreeRDP's server-side input parser skips a six-byte body on unknown slow-path input events without checking the packet length. A remote RDP client with an active session can send a truncated event to trigger a WinPR stream assertion and abort the server process.","severity":"high","cvss":8.7,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["freerdp","linux","package","rdp-server","windows"],"not_affected_if":["client-only","default-release-build","no-rdp-server"],"how_to_check":"- Check the installed FreeRDP version, for example with `xfreerdp /version` or your package manager, and compare against `3.32.2`.\n- Confirm whether your server runs FreeRDP with assertions enabled (debug or non-release builds); the sources do not say which default build setting is affected.","fix":"- FreeRDP `3.0.0` before `3.32.2`: move to `3.32.2`.","status":"open","published_at":"2026-11-04T16:17:47+00:00","first_seen_at":"2026-11-04T16:28:11+00:00","triaged_at":"2026-11-04T16:28:45+00:00","updated_at":"2026-11-04T16:28:45+00:00","category":"package","confidence":0.7,"triage":{"at":"2026-11-04T16:28:45Z","model":"claude-haiku-5-5","output":{"fix":"- FreeRDP `3.0.0` before `3.32.2`: move to `3.32.2`.","reach":"network","title":"FreeRDP: malformed RDP input event crashes server, causing denial of service","impact":"low","summary":"FreeRDP's server-side input parser skips a six-byte body on unknown slow-path input events without checking the packet length. A remote RDP client with an active session can send a truncated event to trigger a WinPR stream assertion and abort the server process.","audience":"businesses","category":"package","nicknames":[],"who_cares":["freerdp","rdp-server","linux","windows"],"confidence":0.7,"fix_status":"available","needs_auth":"yes","worst_case":"remote client aborts the server process, causing denial of service","analyst_note":"","how_to_check":"- Check the installed FreeRDP version, for example with `xfreerdp /version` or your package manager, and compare against `3.32.2`.\n- Confirm whether your server runs FreeRDP with assertions enabled (debug or non-release builds); the sources do not say which default build setting is affected.","plain_action":"","needs_analyst":false,"not_affected_if":["no-rdp-server","client-only","default-release-build"],"who_is_affected":"Only servers built with FreeRDP in the 3.0.0 to before 3.32.2 range that accept RDP sessions from remote clients are exposed. The sources say the crash needs assertion-enabled builds and an active session, so servers that do not run FreeRDP as an RDP server can skip it.","user_interaction":"no","needs_special_setup":"yes","severity_if_unknown":"high"},"cost_usd":0.0007,"input_tokens":4205,"output_tokens":559,"severity_before":"high"},"analyst_status":null,"analyst_note":null,"search":"'-121951':14A,17A '-2026':13A,16A '3.0.0':75C '3.32.2':77C 'abort':70B,135C 'activ':56B,125C 'assert':68B,117C,137C 'assertion-en':136C 'bodi':37B,90C 'byte':36B,89C 'caus':8A,113C,141C 'check':46B,104C 'client':53B,122C 'crash':6A 'cve':12A,15A 'declar':111C 'denial':9A,142C 'enabl':138C 'event':5A,44B,62B,97C,133C 'failur':118C 'freerdp':1A,18B,25B,74C 'input':4A,30B,43B,83C,96C,132C 'length':49B,112C 'lie':106C 'linux':19B 'malform':2A 'messag':101C 'packag':20B 'packet':48B,109C 'pars':84C 'parser':31B 'path':42B,95C 'peer':82C 'process':73B,140C 'rdp':3A,22B,52B,81C,121C 'rdp-server':21B 'remot':51B,120C 'send':59B,128C 'server':7A,23B,28B,72B,79C,139C 'server-sid':27B,78C 'servic':11A,144C 'session':57B,126C 'side':29B,80C 'six':35B,88C 'six-byt':34B,87C 'skip':32B,85C 'slow':41B,94C 'slow-path':40B,93C 'stream':67B,116C 'trigger':64B 'truncat':61B,130C 'type':102C 'unknown':39B,100C,131C 'window':24B 'winpr':66B,115C 'within':107C 'without':45B,103C","nicknames":[],"mitigations":[],"who_affected":"Only servers built with FreeRDP in the 3.0.0 to before 3.32.2 range that accept RDP sessions from remote clients are exposed. The sources say the crash needs assertion-enabled builds and an active session, so servers that do not run FreeRDP as an RDP server can skip it.","tier":"B","verified":{},"analyst_revisit_at":null,"fix_status":"available","audience":"businesses","plain_action":null,"pkeys":[],"ptokens":[],"labels":["freerdp","high","linux","package","rdpserver","windows"],"campaign_type":null,"first_public_at":"2026-10-20T17:13:57+00:00","kev":null,"cvss_vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/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-2026-121951","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-121951","severity":null,"published_at":"2026-11-04T16:17:47+00:00","modified_at":"2026-11-04T16:17:47+00:00","first_seen_at":"2026-11-04T16:28:11+00:00","fetched_at":"2026-11-04T16:28:11+00:00","note":null}],"documents":[{"id":68472,"url":"https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-4qq4-qwxq-49m8","title":"Vendor advisory: github.com","kind":"vendor","source":"nvd","publisher":"vendor","text":null,"published_at":"2026-10-20T17:13:57+00:00","relation":"advisory","confidence":null,"note":"Vendor advisory: github.com"},{"id":68473,"url":"https://www.vulncheck.com/advisories/freerdp-3.0.0-before-3.32.2-denial-of-service-via-slow-path-input-event","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"}