{"id":"CVE-2026-91396","kind":"vulnerability","aliases":["CVE-2026-91396"],"related":[],"title":"Oracle Java SE and GraalVM: network attacker can alter data or cause 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: Utility).  Supported versions that are affected are Oracle Java SE: 8u503, 8u503-perf, 11.0.32.1;    Oracle GraalVM for JDK: 17.0.20.1 and  21.0.12.1;   Oracle GraalVM Enterprise Edition: 21.3.19.1.1. Easily exploitable 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 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 6.5 (Integrity and Availability impacts).  CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L).","summary":"An unauthenticated attacker with network access can exploit a flaw in the Utility component of Oracle Java SE and GraalVM through APIs reached by a web service. Successful attacks can allow unauthorized update, insert or delete of some accessible data and a partial denial of service.","severity":"medium","cvss":6.5,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["graalvm","java","jdk","runtime","self-hosted","web-services"],"not_affected_if":["no-untrusted-network-input","patched-version"],"how_to_check":"- Run `java -version` and compare against the affected releases: Java SE 8u503, 8u503-perf, 11.0.32.1; GraalVM for JDK 17.0.20.1 and 21.0.12.1; GraalVM Enterprise Edition 21.3.19.1.1\n- Check whether any service feeds untrusted network data into Java APIs in the Utility component, such as a web service\n- Check for sandboxed Java Web Start or applet use, which the advisory also covers","fix":"- Upgrade Oracle Java SE to a release newer than 8u503, 8u503-perf or 11.0.32.1 (vendor patch level unknown from sources)\n- Upgrade Oracle GraalVM for JDK to a release newer than 17.0.20.1 or 21.0.12.1\n- Upgrade Oracle GraalVM Enterprise Edition to a release newer than 21.3.19.1.1\n- Apply the vendor's Oracle Critical Patch Update for the affected product line","status":"open","published_at":"2026-10-20T22:20:42+00:00","first_seen_at":"2026-10-23T21:57:26+00:00","triaged_at":"2026-10-25T03:50:49+00:00","updated_at":"2026-10-25T03:50:49+00:00","category":"runtime","confidence":0.7,"triage":{"at":"2026-10-25T03:50:49Z","model":"claude-haiku-5-5","output":{"fix":"- Upgrade Oracle Java SE to a release newer than 8u503, 8u503-perf or 11.0.32.1 (vendor patch level unknown from sources)\n- Upgrade Oracle GraalVM for JDK to a release newer than 17.0.20.1 or 21.0.12.1\n- Upgrade Oracle GraalVM Enterprise Edition to a release newer than 21.3.19.1.1\n- Apply the vendor's Oracle Critical Patch Update for the affected product line","reach":"internet","title":"Oracle Java SE and GraalVM: network attacker can alter data or cause partial denial of service","impact":"medium","summary":"An unauthenticated attacker with network access can exploit a flaw in the Utility component of Oracle Java SE and GraalVM through APIs reached by a web service. Successful attacks can allow unauthorized update, insert or delete of some accessible data and a partial denial of service.","category":"runtime","nicknames":[],"who_cares":["java","jdk","graalvm","web-services","self-hosted"],"confidence":0.7,"needs_auth":"no","worst_case":"Attacker alters or deletes some data and partly disrupts the Java service","analyst_note":"Check the Oracle Critical Patch Update advisory and the NVD entry (https://nvd.nist.gov/vuln/detail/CVE-2026-91396) for the exact Utility component APIs and patched release numbers.","how_to_check":"- Run `java -version` and compare against the affected releases: Java SE 8u503, 8u503-perf, 11.0.32.1; GraalVM for JDK 17.0.20.1 and 21.0.12.1; GraalVM Enterprise Edition 21.3.19.1.1\n- Check whether any service feeds untrusted network data into Java APIs in the Utility component, such as a web service\n- Check for sandboxed Java Web Start or applet use, which the advisory also covers","needs_analyst":true,"not_affected_if":["patched-version","no-untrusted-network-input"],"who_is_affected":"Teams running Oracle Java SE, GraalVM for JDK or GraalVM Enterprise Edition at the listed versions that accept network input through a web service or similar path reaching the affected APIs. The advisory also applies to clients running sandboxed Java Web Start applications or applets that load untrusted code. Teams on other JDK vendors or on patched Oracle releases can skip it.","user_interaction":"no","needs_special_setup":"unknown","severity_if_unknown":"medium"},"cost_usd":0.000821,"input_tokens":3843,"output_tokens":873,"severity_before":"medium"},"analyst_status":null,"analyst_note":null,"search":"'-2026':18A,21A '-91396':19A,22A '/av':283C '11.0.32.1':113C '17.0.20.1':118C '21.0.12.1':120C '21.3.19.1.1':125C '3.1':271C,282C '6.5':274C '8u503':109C,111C '8u503-perf':110C 'abil':183C 'access':38B,71B,134C,164C,179C 'affect':104C 'allow':63B,129C 'also':231C 'alter':9A 'api':54B,213C,228C 'applet':248C 'appli':232C 'applic':244C 'attack':7A,35B,61B,131C,152C 'avail':277C 'base':272C 'caus':12A,185C 'client':238C 'code':254C,256C 'come':258C 'compon':46B,98C,217C 'compromis':139C 'cve':17A,20A 'cvss':270C,279C,281C 'data':10A,72B,180C,225C 'delet':68B,163C 'denial':14A,76B,188C 'deploy':235C 'dos':192C 'e.g':218C,255C 'easili':126C 'edit':92C,124C,150C,178C,204C 'enterpris':91C,123C,149C,177C,203C 'exploit':40B,127C,210C 'flaw':42B 'graalvm':5A,23B,52B,86C,90C,115C,122C,144C,148C,172C,176C,198C,202C 'host':29B 'impact':278C 'insert':66B,161C 'integr':275C 'internet':261C 'java':2A,24B,49B,83C,96C,107C,141C,169C,195C,234C,241C,247C,266C 'jdk':25B,88C,117C,146C,174C,200C 'l':291C 'l/a':290C 'l/pr':285C 'load':250C 'multipl':136C 'n/ac':284C 'n/i':289C 'n/s':287C 'n/ui':286C 'network':6A,37B,133C 'note':205C 'oracl':1A,48B,82C,85C,89C,95C,106C,114C,121C,140C,143C,147C,168C,171C,175C,194C,197C,201C 'partial':13A,75B,187C,191C 'perf':112C 'product':93C 'protocol':137C 'reach':55B 'reli':263C 'result':157C 'run':239C,252C 'runtim':26B 'sandbox':240C,246C,267C 'score':273C 'se':3A,50B,84C,97C,108C,142C,170C,196C 'secur':269C 'self':28B 'self-host':27B 'servic':16A,32B,59B,78B,190C,222C 'specifi':216C 'start':243C 'success':60B,151C 'suppli':224C 'support':100C 'typic':236C 'u/c':288C 'unauthent':34B,130C 'unauthor':64B,159C,182C 'untrust':253C 'updat':65B,160C 'use':212C 'util':45B,99C 'vector':280C 'version':101C 'via':135C 'vulner':79C,128C,155C,207C,230C 'web':31B,58B,221C,242C 'web-servic':30B","nicknames":[],"mitigations":[],"who_affected":"Teams running Oracle Java SE, GraalVM for JDK or GraalVM Enterprise Edition at the listed versions that accept network input through a web service or similar path reaching the affected APIs. The advisory also applies to clients running sandboxed Java Web Start applications or applets that load untrusted code. Teams on other JDK vendors or on patched Oracle releases can skip it.","tier":"C","verified":{},"analyst_revisit_at":null,"first_public_at":"2026-10-20T22:20:42+00:00","kev":null,"cvss_vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L","cvss_by":"secalert_us@oracle.com","poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-91396","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-91396","severity":null,"published_at":"2026-10-20T22:20:42+00:00","modified_at":"2026-10-22T19:18:04+00:00","first_seen_at":"2026-10-23T21:57:26+00:00","fetched_at":"2026-10-23T22:29:00+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"}