{"id":"CVE-2026-91647","kind":"vulnerability","aliases":["CVE-2026-91647"],"related":[],"title":"Oracle Essbase: unauthenticated network flaw allows full takeover of server","description":"Vulnerability in Oracle Essbase (component: Security).   The supported version that is affected is 21.8.3.0.0. Difficult to exploit vulnerability allows unauthenticated attacker with network access via TCP to compromise Oracle Essbase.  Successful attacks of this vulnerability can result in takeover of Oracle Essbase. CVSS 3.1 Base Score 8.1 (Confidentiality, Integrity and Availability impacts).  CVSS Vector: (CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H).","summary":"Oracle Essbase 21.8.3.0.0 has a Security component flaw that an unauthenticated attacker can reach over TCP. Successful exploitation can lead to full takeover of the Essbase server, with high confidentiality, integrity and availability impact.","severity":"high","cvss":8.1,"epss":0.00255,"exploited":false,"exploited_at":null,"products":[{"name":"oracle essbase","fixed":[],"affected":"= 21.8.3.0.0","ecosystem":"vendor"}],"ecosystems":["vendor"],"tags":["on-prem-analytics","oracle-essbase","self-hosted","vendor"],"not_affected_if":["isolated-network","other-version"],"how_to_check":"- Check the installed Essbase version against `21.8.3.0.0`\n- Confirm whether Essbase is reachable from untrusted networks, since the sources say the attack is over TCP\n- Fix version: unknown","fix":"- Apply the Oracle Critical Patch Update that addresses CVE-2026-91647 for Essbase (patch identifier: unknown)\n- Restrict network access to Essbase ports until patched","status":"open","published_at":"2026-10-20T22:21:04+00:00","first_seen_at":"2026-10-23T21:57:27+00:00","triaged_at":"2026-10-25T03:06:00+00:00","updated_at":"2026-10-25T03:06:00+00:00","category":"vendor","confidence":0.6,"triage":{"at":"2026-10-25T03:06:00Z","model":"claude-haiku-5-5","output":{"fix":"- Apply the Oracle Critical Patch Update that addresses CVE-2026-91647 for Essbase (patch identifier: unknown)\n- Restrict network access to Essbase ports until patched","reach":"network","title":"Oracle Essbase: unauthenticated network flaw allows full takeover of server","impact":"high","summary":"Oracle Essbase 21.8.3.0.0 has a Security component flaw that an unauthenticated attacker can reach over TCP. Successful exploitation can lead to full takeover of the Essbase server, with high confidentiality, integrity and availability impact.","category":"vendor","nicknames":[],"who_cares":["oracle-essbase","self-hosted","on-prem-analytics"],"confidence":0.6,"needs_auth":"no","worst_case":"Attacker takes over the Essbase server over the network","analyst_note":"Find the Oracle CPU advisory and patched version for Essbase 21.8.3.0.0 and the exact exploit preconditions (https://nvd.nist.gov/vuln/detail/CVE-2026-91647).","how_to_check":"- Check the installed Essbase version against `21.8.3.0.0`\n- Confirm whether Essbase is reachable from untrusted networks, since the sources say the attack is over TCP\n- Fix version: unknown","needs_analyst":true,"not_affected_if":["isolated-network","other-version"],"who_is_affected":"Teams running Oracle Essbase version 21.8.3.0.0 that expose its TCP service to a network an attacker can reach. The sources do not describe a non-default configuration, so deployments with network reachability should be treated as exposed. Installations not running this version, or with Essbase isolated from untrusted networks, are less exposed.","user_interaction":"no","needs_special_setup":"unknown","severity_if_unknown":"high"},"cost_usd":0.000667,"input_tokens":3477,"output_tokens":639,"severity_before":"high"},"analyst_status":null,"analyst_note":null,"search":"'-2026':12A,15A '-91647':13A,16A '/av':120C '21.8.3.0.0':32B,77C '3.1':107C,119C '8.1':110C 'access':87C 'affect':75C 'allow':6A,82C 'analyt':22B 'attack':41B,84C,95C 'avail':62B,114C 'base':108C 'compon':36B,68C 'compromis':91C 'confidenti':59B,111C 'cve':11A,14A 'cvss':106C,116C,118C 'difficult':78C 'essbas':2A,25B,31B,55B,67C,93C,105C 'essbase':18A 'exploit':47B,80C 'flaw':5A,37B 'full':7A,51B 'h':128C 'h/a':127C 'h/i':126C 'h/pr':122C 'high':58B 'host':28B 'impact':63B,115C 'integr':60B,112C 'lead':49B 'n/ac':121C 'n/s':124C 'n/ui':123C 'network':4A,86C 'on-prem-analyt':19B 'oracl':1A,24B,30B,66C,92C,104C 'oracle':17A 'oracle-essbas':23B 'prem':21B 'reach':43B 'result':100C 'score':109C 'secur':35B,69C 'self':27B 'self-host':26B 'server':10A,56B 'success':46B,94C 'support':71C 'takeov':8A,52B,102C 'tcp':45B,89C 'u/c':125C 'unauthent':3A,40B,83C 'vector':117C 'vendor':29B 'version':72C 'via':88C 'vulner':64C,81C,98C","nicknames":[],"mitigations":[],"who_affected":"Teams running Oracle Essbase version 21.8.3.0.0 that expose its TCP service to a network an attacker can reach. The sources do not describe a non-default configuration, so deployments with network reachability should be treated as exposed. Installations not running this version, or with Essbase isolated from untrusted networks, are less exposed.","tier":"B","verified":{},"analyst_revisit_at":null,"first_public_at":"2026-10-20T22:21:04+00:00","kev":null,"cvss_vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H","cvss_by":"secalert_us@oracle.com","poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-91647","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-91647","severity":null,"published_at":"2026-10-20T22:21:04+00:00","modified_at":"2026-10-23T17:19:13+00:00","first_seen_at":"2026-10-23T21:57:27+00:00","fetched_at":"2026-10-23T22:29:01+00:00","note":null},{"source":"epss","external_id":"CVE-2026-91647","url":"https://api.first.org/data/v1/epss?cve=CVE-2026-91647","severity":null,"published_at":null,"modified_at":null,"first_seen_at":"2026-10-24T13:15:55+00:00","fetched_at":"2026-10-24T13:15:55+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"}