{"id":"CVE-2026-91334","kind":"vulnerability","aliases":["CVE-2026-91334"],"related":[],"title":"Oracle Java SE: ImageIO flaw lets remote attacker read some data","description":"Vulnerability in the Oracle Java SE, Oracle GraalVM for JDK, Oracle GraalVM Enterprise Edition product of Oracle Java SE (component: ImageIO).  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 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 3.7 (Confidentiality impacts).  CVSS Vector: (CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N).","summary":"A flaw in the ImageIO component of Oracle Java SE and GraalVM lets an unauthenticated remote attacker read a subset of accessible data. Exploitation is difficult and is possible through web services that pass data to the affected APIs, and through sandboxed Java applets or Web Start apps.","severity":"low","cvss":3.7,"epss":0.00208,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["graalvm","java","oracle-jdk","runtime","self-hosted"],"not_affected_if":["no-java-installed","patched-release"],"how_to_check":"- Run `java -version` and compare against the affected releases: 8u503, 11.0.32.1, 17.0.20.1, 21.0.12.1, 25.0.4.1, 27.\n- For GraalVM, check the JDK build against 17.0.20.1, 21.0.12.1 and 21.3.19.1.1.\n- Check whether services use ImageIO to parse untrusted image input.","fix":"- Update Oracle Java SE to a patched release for your line, such as `8u503` or later in 8, `11.0.32.1`+ in 11, `17.0.20.1`+ in 17, `21.0.12.1`+ in 21, `25.0.4.1`+ in 25.\n- Update Oracle GraalVM for JDK to `17.0.20.1` or `21.0.12.1` or later.\n- Update Oracle GraalVM Enterprise Edition past `21.3.19.1.1`.","status":"open","published_at":"2026-10-20T22:20:35+00:00","first_seen_at":"2026-10-23T21:57:26+00:00","triaged_at":"2026-10-25T04:43:47+00:00","updated_at":"2026-10-25T12:38:52+00:00","category":"runtime","confidence":0.7,"triage":{"at":"2026-10-25T04:43:47Z","model":"claude-haiku-5-5","output":{"fix":"- Update Oracle Java SE to a patched release for your line, such as `8u503` or later in 8, `11.0.32.1`+ in 11, `17.0.20.1`+ in 17, `21.0.12.1`+ in 21, `25.0.4.1`+ in 25.\n- Update Oracle GraalVM for JDK to `17.0.20.1` or `21.0.12.1` or later.\n- Update Oracle GraalVM Enterprise Edition past `21.3.19.1.1`.","reach":"network","title":"Oracle Java SE: ImageIO flaw lets remote attacker read some data","impact":"low","summary":"A flaw in the ImageIO component of Oracle Java SE and GraalVM lets an unauthenticated remote attacker read a subset of accessible data. Exploitation is difficult and is possible through web services that pass data to the affected APIs, and through sandboxed Java applets or Web Start apps.","category":"runtime","nicknames":[],"who_cares":["java","oracle-jdk","graalvm","self-hosted"],"confidence":0.7,"needs_auth":"no","worst_case":"Attacker reads a subset of accessible data on the server","analyst_note":"","how_to_check":"- Run `java -version` and compare against the affected releases: 8u503, 11.0.32.1, 17.0.20.1, 21.0.12.1, 25.0.4.1, 27.\n- For GraalVM, check the JDK build against 17.0.20.1, 21.0.12.1 and 21.3.19.1.1.\n- Check whether services use ImageIO to parse untrusted image input.","needs_analyst":false,"not_affected_if":["patched-release","no-java-installed"],"who_is_affected":"Teams running Oracle Java SE or GraalVM builds that include the affected releases, especially services that use ImageIO on data from outside the network. Client machines that run untrusted Java applets or Web Start apps are also in scope. Systems on patched releases or without Java installed can skip it.","user_interaction":"no","needs_special_setup":"unknown","severity_if_unknown":"low"},"cost_usd":0.000743,"input_tokens":3801,"output_tokens":726,"severity_before":"low"},"analyst_status":null,"analyst_note":null,"search":"'-2026':13A,16A '-91334':14A,17A '/av':256C '11.0.32.1':109C '17.0.20.1':110C,118C '21.0.12.1':111C,120C '21.3.19.1.1':125C '25.0.4.1':112C '27':113C '3.1':246C,255C '3.7':249C '8u503':105C,107C '8u503-perf':106C 'access':48B,135C,162C,178C 'affect':64B,100C 'allow':130C 'also':206C 'api':65B,188C,203C 'app':74B 'applet':70B,223C 'appli':207C 'applic':219C 'attack':8A,43B,132C,153C 'base':247C 'client':213C 'code':229C,231C 'come':233C 'compon':32B,94C,192C 'compromis':140C 'confidenti':250C 'cve':12A,15A 'cvss':245C,252C,254C 'data':11A,49B,61B,179C,200C 'deploy':210C 'difficult':52B,126C 'e.g':193C,230C 'edit':88C,124C,151C,177C 'enterpris':87C,123C,150C,176C 'exploit':50B,128C,185C 'flaw':5A,28B 'graalvm':18B,38B,82C,86C,115C,122C,145C,149C,171C,175C 'h/pr':258C 'host':26B 'imageio':4A,31B,95C 'impact':251C 'internet':236C 'java':2A,19B,35B,69B,79C,92C,103C,142C,168C,209C,216C,222C,241C 'jdk':22B,84C,117C,147C,173C 'l/i':262C 'let':6A,39B 'load':225C 'multipl':137C 'n':264C 'n/a':263C 'n/ac':257C 'n/s':260C 'n/ui':259C 'network':134C 'note':180C 'oracl':1A,21B,34B,78C,81C,85C,91C,102C,114C,121C,141C,144C,148C,167C,170C,174C 'oracle-jdk':20B 'pass':60B 'perf':108C 'possibl':55B 'product':89C 'protocol':138C 'read':9A,44B,161C 'reli':238C 'remot':7A,42B 'result':158C 'run':214C,227C 'runtim':23B 'sandbox':68B,215C,221C,242C 'score':248C 'se':3A,36B,80C,93C,104C,143C,169C 'secur':244C 'self':25B 'self-host':24B 'servic':58B,197C 'specifi':191C 'start':73B,218C 'subset':46B,165C 'success':152C 'suppli':199C 'support':96C 'typic':211C 'u/c':261C 'unauthent':41B,131C 'unauthor':160C 'untrust':228C 'use':187C 'vector':253C 'version':97C 'via':136C 'vulner':75C,129C,156C,182C,205C 'web':57B,72B,196C,217C","nicknames":[],"mitigations":[],"who_affected":"Teams running Oracle Java SE or GraalVM builds that include the affected releases, especially services that use ImageIO on data from outside the network. Client machines that run untrusted Java applets or Web Start apps are also in scope. Systems on patched releases or without Java installed can skip it.","tier":"C","verified":{},"analyst_revisit_at":null,"first_public_at":"2026-10-20T22:20:35+00:00","kev":null,"cvss_vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N","cvss_by":"secalert_us@oracle.com","poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-91334","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-91334","severity":null,"published_at":"2026-10-20T22:20:35+00:00","modified_at":"2026-10-21T18:44:40+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-2026-91334","url":"https://api.first.org/data/v1/epss?cve=CVE-2026-91334","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"}