{"id":"CVE-2026-91479","kind":"vulnerability","aliases":["CVE-2026-91479"],"related":[],"title":"Oracle Database Server: unauthenticated attacker can crash RDBMS via adjacent network","description":"Vulnerability in the RDBMS component of Oracle Database Server.  Supported versions that are affected are 23.4.0-23.26.3. Easily exploitable vulnerability allows unauthenticated attacker with access to the physical communication segment attached to the hardware where the RDBMS executes to compromise RDBMS.  Successful attacks of this vulnerability can result in unauthorized ability to cause a hang or frequently repeatable crash (complete DOS) of RDBMS. CVSS 3.1 Base Score 6.5 (Availability impacts).  CVSS Vector: (CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H).","summary":"A flaw in the RDBMS component of Oracle Database Server lets an unauthenticated attacker hang or repeatedly crash the database. The attacker needs access to the physical network segment attached to the hardware running the database.","severity":"medium","cvss":6.5,"epss":0.00234,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["database-admins","oracle-database","package","self-hosted"],"not_affected_if":["managed-hosting","version-outside-range"],"how_to_check":"- Check the installed version with `SELECT * FROM v$version;` and compare it to the affected range 23.4.0 through 23.26.3\n- Confirm whether the database server sits on a shared segment reachable from outside the data centre network (unknown if the sources say more)","fix":"- Move Oracle Database Server to a version outside the affected range 23.4.0 to 23.26.3, using the patch named in Oracle's Critical Patch Update advisory (unknown exact patch in the sources)","status":"open","published_at":"2026-10-20T22:20:51+00:00","first_seen_at":"2026-10-23T21:57:27+00:00","triaged_at":"2026-10-25T03:49:26+00:00","updated_at":"2026-10-25T12:38:51+00:00","category":"package","confidence":0.6,"triage":{"at":"2026-10-25T03:49:26Z","model":"claude-haiku-5-5","output":{"fix":"- Move Oracle Database Server to a version outside the affected range 23.4.0 to 23.26.3, using the patch named in Oracle's Critical Patch Update advisory (unknown exact patch in the sources)","reach":"network","title":"Oracle Database Server: unauthenticated attacker can crash RDBMS via adjacent network","impact":"medium","summary":"A flaw in the RDBMS component of Oracle Database Server lets an unauthenticated attacker hang or repeatedly crash the database. The attacker needs access to the physical network segment attached to the hardware running the database.","category":"package","nicknames":[],"who_cares":["oracle-database","self-hosted","database-admins"],"confidence":0.6,"needs_auth":"no","worst_case":"Database hangs or repeatedly crashes, causing denial of service","analyst_note":"Confirm the Oracle Critical Patch Update advisory and the exact patch level that fixes 23.4.0 to 23.26.3.","how_to_check":"- Check the installed version with `SELECT * FROM v$version;` and compare it to the affected range 23.4.0 through 23.26.3\n- Confirm whether the database server sits on a shared segment reachable from outside the data centre network (unknown if the sources say more)","needs_analyst":true,"not_affected_if":["managed-hosting","version-outside-range"],"who_is_affected":"Only deployments running Oracle Database Server versions 23.4.0 through 23.26.3 are listed as affected. The attack needs an attacker on the physical or adjacent network segment attached to the database hardware, so internet-facing or cloud-isolated databases are less exposed. Teams whose database hosts sit on isolated segments can rank this lower.","user_interaction":"no","needs_special_setup":"unknown","severity_if_unknown":"medium"},"cost_usd":0.000659,"input_tokens":3445,"output_tokens":629,"severity_before":"medium"},"analyst_status":null,"analyst_note":null,"search":"'-2026':13A,16A '-91479':14A,17A '/av':138C '23.26.3':80C '23.4.0':79C '3.1':128C,137C '6.5':131C 'a/ac':139C 'abil':114C 'access':51B,88C 'adjac':10A 'admin':20B 'affect':77C 'allow':84C 'attach':57B,94C 'attack':5A,41B,49B,86C,106C 'avail':132C 'base':129C 'caus':116C 'communic':92C 'complet':123C 'compon':33B,68C 'compromis':103C 'crash':7A,45B,122C 'cve':12A,15A 'cvss':127C,134C,136C 'databas':2A,19B,23B,36B,47B,63B,71C 'database-admin':18B 'dos':124C 'easili':81C 'execut':101C 'exploit':82C 'flaw':29B 'frequent':120C 'h':146C 'hang':42B,118C 'hardwar':60B,97C 'host':27B 'impact':133C 'l/pr':140C 'let':38B 'n/a':145C 'n/i':144C 'n/s':142C 'n/ui':141C 'need':50B 'network':11A,55B 'oracl':1A,22B,35B,70C 'oracle-databas':21B 'packag':24B 'physic':54B,91C 'rdbms':8A,32B,67C,100C,104C,126C 'repeat':44B,121C 'result':111C 'run':61B 'score':130C 'segment':56B,93C 'self':26B 'self-host':25B 'server':3A,37B,72C 'success':105C 'support':73C 'u/c':143C 'unauthent':4A,40B,85C 'unauthor':113C 'vector':135C 'version':74C 'via':9A 'vulner':64C,83C,109C","nicknames":[],"mitigations":[],"who_affected":"Only deployments running Oracle Database Server versions 23.4.0 through 23.26.3 are listed as affected. The attack needs an attacker on the physical or adjacent network segment attached to the database hardware, so internet-facing or cloud-isolated databases are less exposed. Teams whose database hosts sit on isolated segments can rank this lower.","tier":"C","verified":{},"analyst_revisit_at":null,"first_public_at":"2026-10-20T22:20:51+00:00","kev":null,"cvss_vector":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","cvss_by":"secalert_us@oracle.com","poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-91479","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-91479","severity":null,"published_at":"2026-10-20T22:20:51+00:00","modified_at":"2026-10-21T18:44:55+00:00","first_seen_at":"2026-10-23T21:57:27+00:00","fetched_at":"2026-10-23T22:29:00+00:00","note":null},{"source":"epss","external_id":"CVE-2026-91479","url":"https://api.first.org/data/v1/epss?cve=CVE-2026-91479","severity":null,"published_at":null,"modified_at":null,"first_seen_at":"2026-10-25T12:38:51+00:00","fetched_at":"2026-10-25T12:38:51+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"}