{"id":"CVE-2026-91402","kind":"vulnerability","aliases":["CVE-2026-91402"],"related":[],"title":"Oracle Java SE and JavaFX: sandbox flaw leaks a subset of data","description":"Vulnerability in the Oracle Java SE, Oracle JavaFX, Oracle GraalVM Enterprise Edition product of Oracle Java SE (component: JavaFX).  Supported versions that are affected are Oracle Java SE: 8u503; Oracle JavaFX: 21.0.12, 25.0.4 and  27; Oracle GraalVM Enterprise Edition: 21.3.19.1.1. Difficult to exploit vulnerability allows unauthenticated attacker with network access via multiple protocols to compromise Oracle Java SE, Oracle JavaFX, 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 read access to a subset of Oracle Java SE, Oracle JavaFX, Oracle GraalVM Enterprise Edition accessible data. Note: This vulnerability 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. This vulnerability does not apply to Java deployments, typically in servers, that load and run only trusted code (e.g., code installed by an administrator). CVSS 3.1 Base Score 3.1 (Confidentiality impacts).  CVSS Vector: (CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:N/A:N).","summary":"A flaw in the JavaFX component of Oracle Java SE, JavaFX and GraalVM Enterprise lets an unauthenticated remote attacker read a subset of data when a person runs untrusted code. The attack needs a hard-to-exploit condition and a user action, and the advisory rates the impact as confidentiality only (CVSS 3.1 3.1, low).","severity":"low","cvss":3.1,"epss":0.00242,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["applets","desktop-clients","graalvm","java","java-web-start","javafx","runtime"],"not_affected_if":["no-untrusted-java-applets","server-only-deployment","trusted-code-only"],"how_to_check":"- Run `java -version` to see which Java SE release is installed; the affected release listed is 8u503.\n- Check the JavaFX version in use (affected: 21.0.12, 25.0.4 and 27) and the GraalVM Enterprise Edition version (affected: 21.3.19.1.1).\n- Note whether the machine runs sandboxed Java Web Start applications or Java applets that load untrusted code from the internet; the advisory says the flaw applies only to those client deployments.","fix":"- Oracle Java SE: move to a patched release listed in Oracle's Critical Patch Update for this CVE (the sources do not name the fixed version): unknown\n- JavaFX: update to a patched release (the sources do not name it): unknown\n- GraalVM Enterprise Edition: update past 21.3.19.1.1 (fixed version not named in the sources): unknown\n- Where Java applets or Web Start apps are not needed, remove them.","status":"open","published_at":"2026-10-20T22:20:43+00:00","first_seen_at":"2026-10-23T21:57:26+00:00","triaged_at":"2026-10-25T04:47:32+00:00","updated_at":"2026-10-25T12:38:52+00:00","category":"runtime","confidence":0.8,"triage":{"at":"2026-10-25T04:47:32Z","model":"claude-haiku-5-5","output":{"fix":"- Oracle Java SE: move to a patched release listed in Oracle's Critical Patch Update for this CVE (the sources do not name the fixed version): unknown\n- JavaFX: update to a patched release (the sources do not name it): unknown\n- GraalVM Enterprise Edition: update past 21.3.19.1.1 (fixed version not named in the sources): unknown\n- Where Java applets or Web Start apps are not needed, remove them.","reach":"internet","title":"Oracle Java SE and JavaFX: sandbox flaw leaks a subset of data","impact":"low","summary":"A flaw in the JavaFX component of Oracle Java SE, JavaFX and GraalVM Enterprise lets an unauthenticated remote attacker read a subset of data when a person runs untrusted code. The attack needs a hard-to-exploit condition and a user action, and the advisory rates the impact as confidentiality only (CVSS 3.1 3.1, low).","category":"runtime","nicknames":[],"who_cares":["java","javafx","graalvm","desktop-clients","java-web-start","applets"],"confidence":0.8,"needs_auth":"no","worst_case":"Attacker reads a subset of accessible data from the Java client.","analyst_note":"","how_to_check":"- Run `java -version` to see which Java SE release is installed; the affected release listed is 8u503.\n- Check the JavaFX version in use (affected: 21.0.12, 25.0.4 and 27) and the GraalVM Enterprise Edition version (affected: 21.3.19.1.1).\n- Note whether the machine runs sandboxed Java Web Start applications or Java applets that load untrusted code from the internet; the advisory says the flaw applies only to those client deployments.","needs_analyst":false,"not_affected_if":["server-only-deployment","trusted-code-only","no-untrusted-java-applets"],"who_is_affected":"The flaw applies to client-side Java deployments, typically sandboxed Java Web Start applications or applets, that load and run untrusted code from the internet and rely on the Java sandbox. The advisory states it does not apply to server deployments that run only code installed by an administrator, so server-only teams can skip it.","user_interaction":"yes","needs_special_setup":"yes","severity_if_unknown":"low"},"cost_usd":0.000773,"input_tokens":3761,"output_tokens":794,"severity_before":"low"},"analyst_status":null,"analyst_note":null,"search":"'-2026':14A,17A '-91402':15A,18A '/av':265C '21.0.12':118C '21.3.19.1.1':126C '25.0.4':119C '27':121C '3.1':84B,85B,255C,258C,264C '8u503':115C 'access':136C,173C,187C 'action':73B 'administr':253C 'advisori':76B 'affect':110C 'allow':131C 'applet':19B,208C 'appli':192C,234C 'applic':204C 'attack':49B,62B,133C,152C,162C,164C 'base':256C 'client':22B,198C 'code':60B,214C,216C,247C,249C 'come':218C 'compon':36B,104C 'compromis':141C 'condit':69B 'confidenti':81B,259C 'cve':13A,16A 'cvss':83B,254C,261C,263C 'data':12A,54B,188C 'deploy':195C,237C 'desktop':21B 'desktop-cli':20B 'difficult':127C 'e.g':215C,248C 'edit':98C,125C,150C,186C 'enterpris':44B,97C,124C,149C,185C 'exploit':68B,129C 'flaw':7A,32B 'graalvm':23B,43B,96C,123C,148C,184C 'h/pr':267C 'hard':66B 'hard-to-exploit':65B 'human':154C 'impact':79B,260C 'instal':250C 'interact':155C 'internet':221C 'java':2A,24B,26B,39B,91C,102C,113C,143C,179C,194C,201C,207C,226C,236C 'java-web-start':25B 'javafx':5A,29B,35B,41B,94C,105C,117C,146C,182C 'l/i':271C 'leak':8A 'let':45B 'load':210C,242C 'low':86B 'multipl':138C 'n':273C 'n/a':272C 'n/ac':266C 'n/ui':268C 'need':63B 'network':135C 'note':189C 'oracl':1A,38B,90C,93C,95C,101C,112C,116C,122C,142C,145C,147C,178C,181C,183C 'person':57B,158C 'product':99C 'protocol':139C 'r/s':269C 'rate':77B 'read':50B,172C 'reli':223C 'remot':48B 'requir':153C 'result':169C 'run':58B,199C,212C,244C 'runtim':30B 'sandbox':6A,200C,206C,227C 'score':257C 'se':3A,40B,92C,103C,114C,144C,180C 'secur':229C 'server':240C 'start':28B,203C 'subset':10A,52B,176C 'success':151C,163C 'support':106C 'trust':246C 'typic':196C,238C 'u/c':270C 'unauthent':47B,132C 'unauthor':171C 'untrust':59B,213C 'user':72B 'vector':262C 'version':107C 'via':137C 'vulner':87C,130C,167C,191C,231C 'web':27B,202C","nicknames":[],"mitigations":[],"who_affected":"The flaw applies to client-side Java deployments, typically sandboxed Java Web Start applications or applets, that load and run untrusted code from the internet and rely on the Java sandbox. The advisory states it does not apply to server deployments that run only code installed by an administrator, so server-only teams 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:N/AC:H/PR:N/UI:R/S:U/C:L/I:N/A:N","cvss_by":"secalert_us@oracle.com","poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-91402","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-91402","severity":null,"published_at":"2026-10-20T22:20:43+00:00","modified_at":"2026-10-23T20:17:28+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-2026-91402","url":"https://api.first.org/data/v1/epss?cve=CVE-2026-91402","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"}