{"id":"CVE-2026-121407","kind":"vulnerability","aliases":["CVE-2026-121407"],"related":[],"title":"FreeRDP: crafted remdesk payload crashes the shadow server, dropping sessions","description":"FreeRDP before 3.32.2 contains a denial of service vulnerability in the shadow server's remdesk_server_thread that allows authenticated clients to crash the process via an inverted PDU length check. Attackers can send an 8192-byte remdesk payload declaring an eight-byte PDU length to trigger a fatal Stream_Seek assertion, aborting the server and dropping sessions.","summary":"FreeRDP's shadow server has an inverted PDU length check in its remdesk thread, so a crafted payload makes the process abort on a Stream_Seek assertion. An authenticated client can take the server down and drop active sessions.","severity":"high","cvss":7.1,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["freerdp","linux","rdp","runtime","shadow-server","windows"],"not_affected_if":["client-only","managed-hosting","no-shadow-server"],"how_to_check":"- Check the FreeRDP version with `xfreerdp --version` or the package manager, and see whether it is below `3.32.2`\n- Confirm whether the shadow server (`freerdp-shadow`) is running and accepting connections","fix":"- FreeRDP: move 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":"2026-11-03T15:22:58+00:00","updated_at":"2026-11-03T15:22:58+00:00","category":"runtime","confidence":0.7,"triage":{"at":"2026-11-03T15:22:58Z","model":"claude-haiku-5-5","output":{"fix":"- FreeRDP: move to `3.32.2` or later","reach":"network","title":"FreeRDP: crafted remdesk payload crashes the shadow server, dropping sessions","impact":"low","summary":"FreeRDP's shadow server has an inverted PDU length check in its remdesk thread, so a crafted payload makes the process abort on a Stream_Seek assertion. An authenticated client can take the server down and drop active sessions.","audience":"businesses","category":"runtime","nicknames":[],"who_cares":["freerdp","shadow-server","rdp","linux","windows"],"confidence":0.7,"fix_status":"available","needs_auth":"yes","worst_case":"Server process aborts and all shadow sessions are dropped","analyst_note":"","how_to_check":"- Check the FreeRDP version with `xfreerdp --version` or the package manager, and see whether it is below `3.32.2`\n- Confirm whether the shadow server (`freerdp-shadow`) is running and accepting connections","plain_action":"","needs_analyst":false,"not_affected_if":["no-shadow-server","client-only","managed-hosting"],"who_is_affected":"Teams running a FreeRDP shadow server, which shares a live desktop session over RDP, are exposed because the crash is triggered by a connected client. Systems that only use FreeRDP as a client, or that do not run the shadow server, are not in the described path. Exposure needs an authenticated session, so the risk is highest where many users can connect.","user_interaction":"no","needs_special_setup":"yes","severity_if_unknown":"unknown"},"cost_usd":0.000695,"input_tokens":4201,"output_tokens":550,"severity_before":"high"},"analyst_status":null,"analyst_note":null,"search":"'-121407':13A,16A '-2026':12A,15A '3.32.2':66C '8192':99C 'abort':46B,117C 'activ':62B 'allow':82C 'assert':51B,116C 'attack':95C 'authent':53B,83C 'byte':100C,107C 'check':34B,94C 'client':54B,84C 'contain':67C 'craft':2A,41B 'crash':5A,86C 'cve':11A,14A 'declar':103C 'denial':69C 'drop':9A,61B,121C 'eight':106C 'eight-byt':105C 'fatal':113C 'freerdp':1A,17B,25B,64C 'invert':31B,91C 'length':33B,93C,109C 'linux':18B 'make':43B 'payload':4A,42B,102C 'pdu':32B,92C,108C 'process':45B,88C 'rdp':19B 'remdesk':3A,37B,78C,101C 'runtim':20B 'seek':50B,115C 'send':97C 'server':8A,23B,28B,58B,76C,79C,119C 'servic':71C 'session':10A,63B,122C 'shadow':7A,22B,27B,75C 'shadow-serv':21B 'stream':49B,114C 'take':56B 'thread':38B,80C 'trigger':111C 'via':89C 'vulner':72C 'window':24B","nicknames":[],"mitigations":[],"who_affected":"Teams running a FreeRDP shadow server, which shares a live desktop session over RDP, are exposed because the crash is triggered by a connected client. Systems that only use FreeRDP as a client, or that do not run the shadow server, are not in the described path. Exposure needs an authenticated session, so the risk is highest where many users can connect.","tier":"B","verified":{},"analyst_revisit_at":null,"fix_status":"available","audience":"businesses","plain_action":null,"pkeys":[],"ptokens":[],"labels":["freerdp","high","linux","rdp","runtime","shadowserver","windows"],"first_public_at":"2026-10-19T12:06:54+00:00","kev":null,"cvss_vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:L/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-2026-121407","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-121407","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":58337,"url":"https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-x8vp-ff7m-294g","title":"Vendor advisory: github.com","kind":"vendor","source":"nvd","publisher":"vendor","text":null,"published_at":"2026-10-19T12:06:54+00:00","relation":"advisory","confidence":null,"note":"Vendor advisory: github.com"},{"id":58338,"url":"https://www.vulncheck.com/advisories/freerdp-before-3.32.2-shadow-server-denial-of-service-via-remdesk-channel","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"}