{"id":"CVE-2026-114645","kind":"vulnerability","aliases":["CVE-2026-114645"],"related":[],"title":"MongoDB C Driver: Windows Kerberos/SSPI length overflow corrupts client memory","description":"A 32-bit integer wraparound in the MongoDB C Driver's Windows-only Kerberos/SSPI authentication code can cause an undersized heap buffer to be allocated when an excessively long credential value is supplied in the client's connection configuration. A party able to control that client-side configuration, in conjunction with the affected authentication mechanism, can cause the driver to write outside the bounds of the allocated buffer. This may result in corruption of client process memory and denial of service of the client application. The issue affects only client builds compiled with the Windows-native authentication backend.","summary":"A 32-bit integer wraparound in the MongoDB C Driver's Windows SSPI authentication code can allocate a heap buffer too small for an oversized credential value. Writing past that buffer can corrupt client process memory and crash the application.","severity":"medium","cvss":5.7,"epss":0.00166,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["c-driver","kerberos","libmongoc","mongodb","package","windows"],"not_affected_if":["hardcoded-config","no-kerberos-or-sspi","non-windows-build"],"how_to_check":"- Check whether the application uses the MongoDB C Driver (libmongoc) on Windows with Kerberos or SSPI authentication.\n- Look at the driver version in the build, for example with `mongoc_get_version()` or the packaged libmongoc version.\n- Confirm whether the connection string or client configuration takes credential values from untrusted input.","fix":null,"status":"open","published_at":"2026-10-22T19:17:38+00:00","first_seen_at":"2026-10-23T21:57:31+00:00","triaged_at":"2026-10-25T04:10:25+00:00","updated_at":"2026-10-25T04:10:25+00:00","category":"package","confidence":0.6,"triage":{"at":"2026-10-25T04:10:25Z","model":"claude-haiku-5-5","output":{"fix":"unknown","reach":"unknown","title":"MongoDB C Driver: Windows Kerberos/SSPI length overflow corrupts client memory","impact":"medium","summary":"A 32-bit integer wraparound in the MongoDB C Driver's Windows SSPI authentication code can allocate a heap buffer too small for an oversized credential value. Writing past that buffer can corrupt client process memory and crash the application.","category":"package","nicknames":[],"who_cares":["mongodb","c-driver","libmongoc","windows","kerberos"],"confidence":0.6,"needs_auth":"unknown","worst_case":"Client process memory is corrupted, crashing the application.","analyst_note":"Fixed version not stated in the sources; check the NVD entry and the MongoDB C Driver release notes for the patched version.","how_to_check":"- Check whether the application uses the MongoDB C Driver (libmongoc) on Windows with Kerberos or SSPI authentication.\n- Look at the driver version in the build, for example with `mongoc_get_version()` or the packaged libmongoc version.\n- Confirm whether the connection string or client configuration takes credential values from untrusted input.","needs_analyst":true,"not_affected_if":["non-windows-build","no-kerberos-or-sspi","hardcoded-config"],"who_is_affected":"Only client builds compiled with the Windows-native authentication backend (SSPI) are affected, and only when the Kerberos or SSPI mechanism is in use. The exposure requires a party that can control the client-side connection configuration, so applications that hardcode their credentials or never accept them from outside can likely skip it. Linux and macOS builds are not described as affected.","user_interaction":"no","needs_special_setup":"yes","severity_if_unknown":"medium"},"cost_usd":0.000653,"input_tokens":3451,"output_tokens":616,"severity_before":"medium"},"analyst_status":null,"analyst_note":null,"search":"'-114645':13A,16A '-2026':12A,15A '32':26B,66C 'abl':107C 'affect':119C,154C 'alloc':41B,90C,133C 'applic':64B,151C 'authent':38B,80C,120C,164C 'backend':165C 'bit':27B,67C 'bound':130C 'buffer':44B,55B,87C,134C 'build':157C 'c':2A,18B,33B,73C 'c-driver':17B 'caus':83C,123C 'client':9A,58B,101C,112C,141C,150C,156C 'client-sid':111C 'code':39B,81C 'compil':158C 'configur':104C,114C 'conjunct':116C 'connect':103C 'control':109C 'corrupt':8A,57B,139C 'crash':62B 'credenti':50B,95C 'cve':11A,14A 'denial':145C 'driver':3A,19B,34B,74C,125C 'excess':93C 'heap':43B,86C 'integ':28B,68C 'issu':153C 'kerbero':20B 'kerberos/sspi':5A,79C 'length':6A 'libmongoc':21B 'long':94C 'may':136C 'mechan':121C 'memori':10A,60B,143C 'mongodb':1A,22B,32B,72C 'nativ':163C 'outsid':128C 'overflow':7A 'overs':49B 'packag':23B 'parti':106C 'past':53B 'process':59B,142C 'result':137C 'servic':147C 'side':113C 'small':46B 'sspi':37B 'suppli':98C 'unders':85C 'valu':51B,96C 'window':4A,24B,36B,77C,162C 'windows-n':161C 'windows-on':76C 'wraparound':29B,69C 'write':52B,127C","nicknames":[],"mitigations":[],"who_affected":"Only client builds compiled with the Windows-native authentication backend (SSPI) are affected, and only when the Kerberos or SSPI mechanism is in use. The exposure requires a party that can control the client-side connection configuration, so applications that hardcode their credentials or never accept them from outside can likely skip it. Linux and macOS builds are not described as affected.","tier":"C","verified":{},"analyst_revisit_at":null,"first_public_at":"2026-10-22T19:17:38+00:00","kev":null,"cvss_vector":"CVSS:4.0/AV:L/AC:H/AT:P/PR:H/UI:N/VC:L/VI:L/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":"cna@mongodb.com","poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-114645","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-114645","severity":null,"published_at":"2026-10-22T19:17:38+00:00","modified_at":"2026-10-23T19:45:03+00:00","first_seen_at":"2026-10-23T21:57:31+00:00","fetched_at":"2026-10-23T22:29:02+00:00","note":null},{"source":"epss","external_id":"CVE-2026-114645","url":"https://api.first.org/data/v1/epss?cve=CVE-2026-114645","severity":null,"published_at":null,"modified_at":null,"first_seen_at":"2026-10-24T07:15:51+00:00","fetched_at":"2026-10-24T07:15:51+00:00","note":null}],"documents":[],"notice":"Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai"}