{"id":"CVE-2026-121393","kind":"vulnerability","aliases":["CVE-2026-121393"],"related":[],"title":"FreeRDP: crafted RemoteFX rectangles crash RDP clients built with verbose assertions","description":"FreeRDP from 3.0.0 before 3.32.2 contains a denial of service vulnerability that allows malicious RDP servers to abort clients built with verbose WinPR assertions by sending crafted RemoteFX region rectangles. Attackers can supply a rectangle with x set to 65535 alongside a SurfaceBits destination left of 1, triggering a 16-bit coordinate assertion in rfx_process_message that terminates the client process.","summary":"FreeRDP from 3.0.0 before 3.32.2 lets a malicious RDP server send crafted RemoteFX region rectangles that trigger a 16-bit coordinate assertion in rfx_process_message. The assertion terminates the client process, causing a denial of service.","severity":"high","cvss":7.1,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["c","freerdp","package","rdp","remote-desktop"],"not_affected_if":["default-build-config","trusted-servers-only"],"how_to_check":"- Check the FreeRDP version installed on client machines or in the application's dependencies, for example with `xfreerdp --version`.\n- Confirm whether the build uses verbose WinPR assertions, which the sources say is required for the crash.","fix":"- FreeRDP: move to `3.32.2` or later, per the NVD range.","status":"open","published_at":"2026-11-03T15:17:26+00:00","first_seen_at":"2026-11-03T15:21:57+00:00","triaged_at":"2026-11-03T15:23:06+00:00","updated_at":"2026-11-03T15:23:06+00:00","category":"package","confidence":0.7,"triage":{"at":"2026-11-03T15:23:06Z","model":"claude-haiku-5-5","output":{"fix":"- FreeRDP: move to `3.32.2` or later, per the NVD range.","reach":"network","title":"FreeRDP: crafted RemoteFX rectangles crash RDP clients built with verbose assertions","impact":"low","summary":"FreeRDP from 3.0.0 before 3.32.2 lets a malicious RDP server send crafted RemoteFX region rectangles that trigger a 16-bit coordinate assertion in rfx_process_message. The assertion terminates the client process, causing a denial of service.","audience":"developers","category":"package","nicknames":[],"who_cares":["freerdp","rdp","remote-desktop","c"],"confidence":0.7,"fix_status":"available","needs_auth":"no","worst_case":"Client process terminates, causing denial of service","analyst_note":"","how_to_check":"- Check the FreeRDP version installed on client machines or in the application's dependencies, for example with `xfreerdp --version`.\n- Confirm whether the build uses verbose WinPR assertions, which the sources say is required for the crash.","plain_action":"","needs_analyst":false,"not_affected_if":["trusted-servers-only","default-build-config"],"who_is_affected":"Only FreeRDP clients built with verbose WinPR assertions can be crashed, and the trigger comes from a malicious RDP server the client connects to. Teams that only run FreeRDP against trusted servers, or use non-verbose builds, are less exposed. The sources do not say whether other clients are affected.","user_interaction":"unknown","needs_special_setup":"yes","severity_if_unknown":"unknown"},"cost_usd":0.000701,"input_tokens":4223,"output_tokens":557,"severity_before":"high"},"analyst_status":null,"analyst_note":null,"search":"'-121393':14A,17A '-2026':13A,16A '1':108C '16':43B,111C '3.0.0':27B,64C '3.32.2':29B,66C '65535':101C 'abort':79C 'allow':74C 'alongsid':102C 'assert':11A,46B,52B,85C,114C 'attack':92C 'bit':44B,112C 'built':8A,81C 'c':18B 'caus':57B 'client':7A,55B,80C,122C 'contain':67C 'coordin':45B,113C 'craft':2A,36B,88C 'crash':5A 'cve':12A,15A 'denial':59B,69C 'desktop':24B 'destin':105C 'freerdp':1A,19B,25B,62C 'left':106C 'let':30B 'malici':32B,75C 'messag':50B,118C 'packag':20B 'process':49B,56B,117C,123C 'rdp':6A,21B,33B,76C 'rectangl':4A,39B,91C,96C 'region':38B,90C 'remot':23B 'remote-desktop':22B 'remotefx':3A,37B,89C 'rfx':48B,116C 'send':35B,87C 'server':34B,77C 'servic':61B,71C 'set':99C 'suppli':94C 'surfacebit':104C 'termin':53B,120C 'trigger':41B,109C 'verbos':10A,83C 'vulner':72C 'winpr':84C 'x':98C","nicknames":[],"mitigations":[],"who_affected":"Only FreeRDP clients built with verbose WinPR assertions can be crashed, and the trigger comes from a malicious RDP server the client connects to. Teams that only run FreeRDP against trusted servers, or use non-verbose builds, are less exposed. The sources do not say whether other clients are affected.","tier":"B","verified":{},"analyst_revisit_at":null,"fix_status":"available","audience":"developers","plain_action":null,"pkeys":[],"ptokens":[],"labels":["c","freerdp","high","package","rdp","remotedesktop"],"first_public_at":"2026-10-19T12:04:37+00:00","kev":null,"cvss_vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/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-2026-121393","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-121393","severity":null,"published_at":"2026-11-03T15:17:26+00:00","modified_at":"2026-11-03T15:17:27+00:00","first_seen_at":"2026-11-03T15:21:57+00:00","fetched_at":"2026-11-03T15:21:57+00:00","note":null}],"documents":[{"id":58309,"url":"https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-7qw2-8h66-pvpw","title":"Vendor advisory: github.com","kind":"vendor","source":"nvd","publisher":"vendor","text":null,"published_at":"2026-10-19T12:04:37+00:00","relation":"advisory","confidence":null,"note":"Vendor advisory: github.com"},{"id":58310,"url":"https://www.vulncheck.com/advisories/freerdp-3.0.0-before-3.32.2-denial-of-service-via-remotefx-region-assertion","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"}