{"id":"CVE-2026-91397","kind":"vulnerability","aliases":["CVE-2026-91397"],"related":[],"title":"Oracle Java SE: serviceability component flaw allows limited data change and partial denial of service","description":"Vulnerability in the Oracle Java SE, Oracle GraalVM for JDK, Oracle GraalVM Enterprise Edition product of Oracle Java SE (component: Serviceability).  Supported versions that are affected are Oracle Java SE: 8u503, 8u503-perf, 11.0.32.1, 17.0.20.1, 21.0.12.1, 25.0.4.1, 27; Oracle GraalVM for JDK: 17.0.20.1 and  21.0.12.1; Oracle GraalVM Enterprise Edition: 21.3.19.1.1. Difficult to exploit vulnerability allows unauthenticated attacker with logon to the infrastructure where Oracle Java SE, Oracle GraalVM for JDK, Oracle GraalVM Enterprise Edition executes to compromise Oracle Java SE, Oracle GraalVM for JDK, Oracle GraalVM Enterprise Edition.  Successful attacks require human interaction from a person other than the attacker. Successful attacks of this vulnerability can result in  unauthorized update, insert or delete access to some of Oracle Java SE, Oracle GraalVM for JDK, Oracle GraalVM Enterprise Edition accessible data and unauthorized ability to cause a partial denial of service (partial DOS) of Oracle Java SE, Oracle GraalVM for JDK, Oracle GraalVM Enterprise Edition. Note: This vulnerability can be exploited by using APIs in the specified Component, e.g., through a web service which supplies data to the APIs. This vulnerability also applies to Java deployments, typically in clients running sandboxed Java Web Start applications or sandboxed Java applets, that load and run untrusted code (e.g., code that comes from the internet) and rely on the Java sandbox for security. CVSS 3.1 Base Score 3.6 (Integrity and Availability impacts).  CVSS Vector: (CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:N/I:L/A:L).","summary":"A flaw in the Serviceability component of Oracle Java SE and GraalVM lets an attacker who can reach the runtime change some data or partly disrupt the service. Exploitation is hard and needs a person other than the attacker to take an action, such as a user running untrusted Java code.","severity":"low","cvss":3.6,"epss":0.00094,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["graalvm","java","jvm","runtime","self-hosted"],"not_affected_if":["non-oracle-jdk","patched-version"],"how_to_check":"- Run `java -version` and compare the output against the affected versions listed in the Oracle advisory.\n- For GraalVM, run `native-image --version` or `java -version` and check against `21.3.19.1.1`, `17.0.20.1` or `21.0.12.1`.","fix":"- Move Oracle Java SE to a patched release: `8u503`, `11.0.32.1`, `17.0.20.1`, `21.0.12.1` or `25.0.4.1`, or a later release.\n- Move Oracle GraalVM for JDK to `17.0.20.1` or `21.0.12.1`, and Oracle GraalVM Enterprise Edition to a patched build after `21.3.19.1.1`.","status":"open","published_at":"2026-10-20T22:20:43+00:00","first_seen_at":"2026-10-23T21:57:26+00:00","triaged_at":"2026-10-25T04:45:24+00:00","updated_at":"2026-10-25T12:38:52+00:00","category":"runtime","confidence":0.6,"triage":{"at":"2026-10-25T04:45:24Z","model":"claude-haiku-5-5","output":{"fix":"- Move Oracle Java SE to a patched release: `8u503`, `11.0.32.1`, `17.0.20.1`, `21.0.12.1` or `25.0.4.1`, or a later release.\n- Move Oracle GraalVM for JDK to `17.0.20.1` or `21.0.12.1`, and Oracle GraalVM Enterprise Edition to a patched build after `21.3.19.1.1`.","reach":"network","title":"Oracle Java SE: serviceability component flaw allows limited data change and partial denial of service","impact":"low","summary":"A flaw in the Serviceability component of Oracle Java SE and GraalVM lets an attacker who can reach the runtime change some data or partly disrupt the service. Exploitation is hard and needs a person other than the attacker to take an action, such as a user running untrusted Java code.","category":"runtime","nicknames":[],"who_cares":["java","jvm","graalvm","self-hosted"],"confidence":0.6,"needs_auth":"no","worst_case":"Limited data changes and partial service disruption in the Java runtime","analyst_note":"","how_to_check":"- Run `java -version` and compare the output against the affected versions listed in the Oracle advisory.\n- For GraalVM, run `native-image --version` or `java -version` and check against `21.3.19.1.1`, `17.0.20.1` or `21.0.12.1`.","needs_analyst":false,"not_affected_if":["patched-version","non-oracle-jdk"],"who_is_affected":"Teams that run the affected Oracle Java SE or GraalVM builds on servers, clients or build hosts are exposed. Exposure is greater where Java applets or Web Start applications run untrusted code, since the sandbox is the defence. Teams on other JDK distributions or on patched Oracle releases can skip it.","user_interaction":"yes","needs_special_setup":"unknown","severity_if_unknown":"low"},"cost_usd":0.000727,"input_tokens":3937,"output_tokens":667,"severity_before":"low"},"analyst_status":null,"analyst_note":null,"search":"'-2026':17A,20A '-91397':18A,21A '/av':313C '11.0.32.1':114C '17.0.20.1':115C,123C '21.0.12.1':116C,125C '21.3.19.1.1':130C '25.0.4.1':117C '27':118C '3.1':301C,312C '3.6':304C '8u503':110C,112C '8u503-perf':111C 'abil':213C 'access':194C,209C 'action':71B 'affect':105C 'allow':7A,135C 'also':261C 'api':243C,258C 'applet':278C 'appli':262C 'applic':274C 'attack':43B,67B,137C,170C,180C,182C 'avail':307C 'base':302C 'caus':215C 'chang':10A,49B 'client':268C 'code':79B,284C,286C 'come':288C 'compon':5A,34B,99C,247C 'compromis':157C 'cve':16A,19A 'cvss':300C,309C,311C 'data':9A,51B,210C,255C 'delet':193C 'denial':13A,218C 'deploy':265C 'difficult':131C 'disrupt':54B 'dos':222C 'e.g':248C,285C 'edit':93C,129C,154C,168C,208C,234C 'enterpris':92C,128C,153C,167C,207C,233C 'execut':155C 'exploit':57B,133C,240C 'flaw':6A,30B 'graalvm':22B,40B,87C,91C,120C,127C,148C,152C,162C,166C,202C,206C,228C,232C 'h/pr':315C 'hard':59B 'host':28B 'human':172C 'impact':308C 'infrastructur':142C 'insert':191C 'integr':305C 'interact':173C 'internet':291C 'java':2A,23B,37B,78B,84C,97C,108C,145C,159C,199C,225C,264C,271C,277C,296C 'jdk':89C,122C,150C,164C,204C,230C 'jvm':24B 'l':321C 'l/a':320C 'l/ac':314C 'let':41B 'limit':8A 'load':280C 'logon':139C 'n/i':319C 'n/ui':316C 'need':61B 'note':235C 'oracl':1A,36B,83C,86C,90C,96C,107C,119C,126C,144C,147C,151C,158C,161C,165C,198C,201C,205C,224C,227C,231C 'part':53B 'partial':12A,217C,221C 'perf':113C 'person':63B,176C 'product':94C 'r/s':317C 'reach':46B 'reli':293C 'requir':171C 'result':187C 'run':76B,269C,282C 'runtim':25B,48B 'sandbox':270C,276C,297C 'score':303C 'se':3A,38B,85C,98C,109C,146C,160C,200C,226C 'secur':299C 'self':27B 'self-host':26B 'servic':4A,15A,33B,56B,100C,220C,252C 'specifi':246C 'start':273C 'success':169C,181C 'suppli':254C 'support':101C 'take':69B 'typic':266C 'u/c':318C 'unauthent':136C 'unauthor':189C,212C 'untrust':77B,283C 'updat':190C 'use':242C 'user':75B 'vector':310C 'version':102C 'vulner':80C,134C,185C,237C,260C 'web':251C,272C","nicknames":[],"mitigations":[],"who_affected":"Teams that run the affected Oracle Java SE or GraalVM builds on servers, clients or build hosts are exposed. Exposure is greater where Java applets or Web Start applications run untrusted code, since the sandbox is the defence. Teams on other JDK distributions or on patched Oracle releases can skip it.","tier":"C","verified":{},"analyst_revisit_at":null,"first_public_at":"2026-10-20T22:20:43+00:00","kev":null,"cvss_vector":"CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:N/I:L/A:L","cvss_by":"secalert_us@oracle.com","poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-91397","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-91397","severity":null,"published_at":"2026-10-20T22:20:43+00:00","modified_at":"2026-10-23T03:16:31+00:00","first_seen_at":"2026-10-23T21:57:26+00:00","fetched_at":"2026-10-23T22:29:00+00:00","note":null},{"source":"epss","external_id":"CVE-2026-91397","url":"https://api.first.org/data/v1/epss?cve=CVE-2026-91397","severity":null,"published_at":null,"modified_at":null,"first_seen_at":"2026-10-25T12:38:52+00:00","fetched_at":"2026-10-25T12:38:52+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"}