{"id":"CVE-2026-121956","kind":"vulnerability","aliases":["CVE-2026-121956"],"related":[],"title":"FreeRDP: double free in Kerberos SSPI lets unauthenticated clients crash server","description":"FreeRDP before 3.32.2 contains a double free in the WinPR Kerberos SSPI retrieveSomeTgt function, which installs the krb5 default realm into a target principal that has an empty realm without taking ownership of it. Unauthenticated remote clients can send a crafted NLA/CredSSP u2u TGT request whose server-name component contains '@' to corrupt the heap and crash the server process.","summary":"FreeRDP before 3.32.2 has a double free in the WinPR Kerberos SSPI code path that handles a crafted NLA/CredSSP u2u TGT request. An unauthenticated remote client can corrupt the heap and crash the server process.","severity":"high","cvss":8.7,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["freerdp","kerberos","package","rdp-server","winpr"],"not_affected_if":["fixed-version","no-rdp-server"],"how_to_check":"- Check the FreeRDP version the server runs, for example with `xfreerdp --version` or your package manager's query, and compare it to `3.32.2`.\n- Confirm whether the server accepts NLA/CredSSP connections, which the sources describe as the reachable path.","fix":"- FreeRDP: move to `3.32.2` or later.","status":"open","published_at":"2026-11-04T16:17:48+00:00","first_seen_at":"2026-11-04T16:28:11+00:00","triaged_at":"2026-11-04T16:28:42+00:00","updated_at":"2026-11-04T16:28:42+00:00","category":"package","confidence":0.6,"triage":{"at":"2026-11-04T16:28:42Z","model":"claude-haiku-5-5","output":{"fix":"- FreeRDP: move to `3.32.2` or later.","reach":"network","title":"FreeRDP: double free in Kerberos SSPI lets unauthenticated clients crash server","impact":"low","summary":"FreeRDP before 3.32.2 has a double free in the WinPR Kerberos SSPI code path that handles a crafted NLA/CredSSP u2u TGT request. An unauthenticated remote client can corrupt the heap and crash the server process.","audience":"businesses","category":"package","nicknames":[],"who_cares":["freerdp","rdp-server","winpr","kerberos"],"confidence":0.6,"fix_status":"available","needs_auth":"no","worst_case":"Server process crashes; denial of service reachable without credentials","analyst_note":"Confirm whether NLA/CredSSP is enabled by default and whether code execution is possible beyond the crash, using the vendor advisory linked from github.com.","how_to_check":"- Check the FreeRDP version the server runs, for example with `xfreerdp --version` or your package manager's query, and compare it to `3.32.2`.\n- Confirm whether the server accepts NLA/CredSSP connections, which the sources describe as the reachable path.","plain_action":"","needs_analyst":true,"not_affected_if":["fixed-version","no-rdp-server"],"who_is_affected":"Systems running a FreeRDP-based RDP server before 3.32.2 with NLA/CredSSP reachable by remote clients. The sources describe a crash of the server process, not code execution, and do not say whether client-only use of FreeRDP is affected.","user_interaction":"no","needs_special_setup":"unknown","severity_if_unknown":"unknown"},"cost_usd":0.000717,"input_tokens":4214,"output_tokens":592,"severity_before":"high"},"analyst_status":null,"analyst_note":null,"search":"'-121956':14A,17A '-2026':13A,16A '3.32.2':27B,62C 'client':9A,50B,96C 'code':37B 'compon':109C 'contain':63C,110C 'corrupt':52B,112C 'craft':42B,100C 'crash':10A,56B,116C 'cve':12A,15A 'default':78C 'doubl':2A,30B,65C 'empti':87C 'free':3A,31B,66C 'freerdp':1A,18B,25B,60C 'function':73C 'handl':40B 'heap':54B,114C 'instal':75C 'kerbero':5A,19B,35B,70C 'krb5':77C 'let':7A 'name':108C 'nla/credssp':43B,101C 'ownership':91C 'packag':20B 'path':38B 'princip':83C 'process':59B,119C 'rdp':22B 'rdp-server':21B 'realm':79C,88C 'remot':49B,95C 'request':46B,104C 'retrievesometgt':72C 'send':98C 'server':11A,23B,58B,107C,118C 'server-nam':106C 'sspi':6A,36B,71C 'take':90C 'target':82C 'tgt':45B,103C 'u2u':44B,102C 'unauthent':8A,48B,94C 'whose':105C 'winpr':24B,34B,69C 'without':89C","nicknames":[],"mitigations":[],"who_affected":"Systems running a FreeRDP-based RDP server before 3.32.2 with NLA/CredSSP reachable by remote clients. The sources describe a crash of the server process, not code execution, and do not say whether client-only use of FreeRDP is affected.","tier":"B","verified":{},"analyst_revisit_at":null,"fix_status":"available","audience":"businesses","plain_action":null,"pkeys":[],"ptokens":[],"labels":["freerdp","high","kerberos","package","rdpserver","winpr"],"campaign_type":null,"first_public_at":"2026-10-20T17:11:42+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-2026-121956","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-121956","severity":null,"published_at":"2026-11-04T16:17:48+00:00","modified_at":"2026-11-04T16:17:48+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":68482,"url":"https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-2557-79qc-6gfr","title":"Vendor advisory: github.com","kind":"vendor","source":"nvd","publisher":"vendor","text":null,"published_at":"2026-10-20T17:11:42+00:00","relation":"advisory","confidence":null,"note":"Vendor advisory: github.com"},{"id":68483,"url":"https://www.vulncheck.com/advisories/freerdp-before-3.32.2-double-free-in-winpr-kerberos-retrievesometgt","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"}