{"id":"CVE-2026-91374","kind":"vulnerability","aliases":["CVE-2026-91374"],"related":[],"title":"Oracle Java SE: Serviceability flaw lets remote attackers read and change some data","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 network access via multiple protocols to compromise Oracle Java SE, Oracle GraalVM for JDK, Oracle GraalVM Enterprise Edition.  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 as well as  unauthorized read access to a subset of Oracle Java SE, Oracle GraalVM for JDK, Oracle GraalVM Enterprise Edition accessible data. 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 4.8 (Confidentiality and Integrity impacts).  CVSS Vector: (CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N).","summary":"A flaw in the Serviceability component of Oracle Java SE and GraalVM lets an unauthenticated attacker over the network read and modify a subset of accessible data, via APIs exposed through a web service. The CVSS score is 4.8 (medium), and the attack is hard to carry out.","severity":"medium","cvss":4.8,"epss":0.00168,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["graalvm","java","oracle-java","runtime","self-hosted"],"not_affected_if":["no-exposed-serviceability-api","unaffected-version"],"how_to_check":"- Run `java -version` and compare against the fixed releases listed in the fix.\n- Check whether the application exposes a web service that passes untrusted input to Java Serviceability APIs; the sources do not name the specific APIs.","fix":"- Update Oracle Java SE to a patched release from the Oracle Critical Patch Update for the affected lines (8u503, 11.0.32.1, 17.0.20.1, 21.0.12.1, 25.0.4.1, 27); the affected versions are the ones listed in the advisory, so move to the next release on your line.\n- Update Oracle GraalVM for JDK 17.0.20.1 and 21.0.12.1 and Oracle GraalVM Enterprise Edition 21.3.19.1.1 to their patched builds.\n- Oracle has not stated a specific patched build number in the sources; unknown beyond the Critical Patch Update.","status":"open","published_at":"2026-10-20T22:20:40+00:00","first_seen_at":"2026-10-23T21:57:26+00:00","triaged_at":"2026-10-25T04:33:13+00:00","updated_at":"2026-10-25T12:38:52+00:00","category":"runtime","confidence":0.7,"triage":{"at":"2026-10-25T04:33:13Z","model":"claude-haiku-5-5","output":{"fix":"- Update Oracle Java SE to a patched release from the Oracle Critical Patch Update for the affected lines (8u503, 11.0.32.1, 17.0.20.1, 21.0.12.1, 25.0.4.1, 27); the affected versions are the ones listed in the advisory, so move to the next release on your line.\n- Update Oracle GraalVM for JDK 17.0.20.1 and 21.0.12.1 and Oracle GraalVM Enterprise Edition 21.3.19.1.1 to their patched builds.\n- Oracle has not stated a specific patched build number in the sources; unknown beyond the Critical Patch Update.","reach":"internet","title":"Oracle Java SE: Serviceability flaw lets remote attackers read and change some data","impact":"medium","summary":"A flaw in the Serviceability component of Oracle Java SE and GraalVM lets an unauthenticated attacker over the network read and modify a subset of accessible data, via APIs exposed through a web service. The CVSS score is 4.8 (medium), and the attack is hard to carry out.","category":"runtime","nicknames":[],"who_cares":["java","oracle-java","graalvm","self-hosted"],"confidence":0.7,"needs_auth":"no","worst_case":"Attacker reads and modifies some application data over the network","analyst_note":"","how_to_check":"- Run `java -version` and compare against the fixed releases listed in the fix.\n- Check whether the application exposes a web service that passes untrusted input to Java Serviceability APIs; the sources do not name the specific APIs.","needs_analyst":false,"not_affected_if":["unaffected-version","no-exposed-serviceability-api"],"who_is_affected":"Teams running affected Oracle Java SE or GraalVM builds that serve network-facing web services which feed data into the Serviceability APIs. Client deployments running untrusted Java Web Start or applets are also named as affected. Teams on unaffected versions or without such exposed services can skip it.","user_interaction":"unknown","needs_special_setup":"unknown","severity_if_unknown":"medium"},"cost_usd":0.000751,"input_tokens":3871,"output_tokens":727,"severity_before":"medium"},"analyst_status":null,"analyst_note":null,"search":"'-2026':15A,18A '-91374':16A,19A '/av':284C '11.0.32.1':110C '17.0.20.1':111C,119C '21.0.12.1':112C,121C '21.3.19.1.1':126C '25.0.4.1':113C '27':114C '3.1':272C,283C '4.8':67B,275C '8u503':106C,108C '8u503-perf':107C 'access':54B,136C,166C,181C,188C,204C 'affect':101C 'allow':131C 'also':232C 'api':57B,214C,229C 'applet':249C 'appli':233C 'applic':245C 'attack':8A,44B,71B,133C,154C 'base':273C 'carri':75B 'chang':11A 'client':239C 'code':255C,257C 'come':259C 'compon':34B,95C,218C 'compromis':141C 'confidenti':276C 'cve':14A,17A 'cvss':64B,271C,280C,282C 'data':13A,55B,182C,205C,226C 'delet':165C 'deploy':236C 'difficult':127C 'e.g':219C,256C 'edit':89C,125C,152C,180C,203C 'enterpris':88C,124C,151C,179C,202C 'exploit':129C,211C 'expos':58B 'flaw':5A,30B 'graalvm':20B,40B,83C,87C,116C,123C,146C,150C,174C,178C,197C,201C 'h/pr':286C 'hard':73B 'host':28B 'impact':279C 'insert':163C 'integr':278C 'internet':262C 'java':2A,21B,24B,37B,80C,93C,104C,143C,171C,194C,235C,242C,248C,267C 'jdk':85C,118C,148C,176C,199C 'l/a':291C 'l/i':290C 'let':6A,41B 'load':251C 'medium':68B 'modifi':50B 'multipl':138C 'n':292C 'n/ac':285C 'n/s':288C 'n/ui':287C 'network':47B,135C 'note':206C 'oracl':1A,23B,36B,79C,82C,86C,92C,103C,115C,122C,142C,145C,149C,170C,173C,177C,193C,196C,200C 'oracle-java':22B 'perf':109C 'product':90C 'protocol':139C 'read':9A,48B,187C 'reli':264C 'remot':7A 'result':159C 'run':240C,253C 'runtim':25B 'sandbox':241C,247C,268C 'score':65B,274C 'se':3A,38B,81C,94C,105C,144C,172C,195C 'secur':270C 'self':27B 'self-host':26B 'servic':4A,33B,62B,96C,223C 'specifi':217C 'start':244C 'subset':52B,191C 'success':153C 'suppli':225C 'support':97C 'typic':237C 'u/c':289C 'unauthent':43B,132C 'unauthor':161C,186C 'untrust':254C 'updat':162C 'use':213C 'vector':281C 'version':98C 'via':56B,137C 'vulner':76C,130C,157C,208C,231C 'web':61B,222C,243C 'well':184C","nicknames":[],"mitigations":[],"who_affected":"Teams running affected Oracle Java SE or GraalVM builds that serve network-facing web services which feed data into the Serviceability APIs. Client deployments running untrusted Java Web Start or applets are also named as affected. Teams on unaffected versions or without such exposed services can skip it.","tier":"C","verified":{},"analyst_revisit_at":null,"first_public_at":"2026-10-20T22:20:40+00:00","kev":null,"cvss_vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N","cvss_by":"secalert_us@oracle.com","poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-91374","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-91374","severity":null,"published_at":"2026-10-20T22:20:40+00:00","modified_at":"2026-10-21T18:45:11+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-2026-91374","url":"https://api.first.org/data/v1/epss?cve=CVE-2026-91374","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"}