Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain
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AccessHost malicious Java applet/Web Start app
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ExploitLure victim to load untrusted code
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ExecutionExploit JGSS sandbox weakness
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ImpactRead critical confidential data
Vulnerability Assessment
| Weakness |
CWE
ASVS 5.0
V15 - Secure Coding and Architecture Memory lifecycle management
MITRE ATT&CK
2 techniques across 2 tactics: Execution, Privilege Escalation The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up. |
| Exploitation Conditions | Exploitable ONLY in Java client deployments that run sandboxed Java Web Start applications or sandboxed Java applets which load and execute untrusted code (e.g., code fetched from the internet) and rely on the Java sandbox for security, via the JGSS component. It explicitly does NOT apply to server deployments that load and run only trusted/admin-installed code. Exploitation is limited by HIGH attack complexity (Oracle: 'difficult to exploit'), by required human interaction from a victim other than the attacker (UI:R - the victim must actively launch the untrusted application), and by the near-obsolescence of browser applet and Web Start support in current JDK/browser versions. |
| Impact | This is a moderate-severity confidentiality issue (CVSS 3.1 base 5.3) whose real-world priority is LOW despite affecting an ubiquitous runtime, because the exploitability preconditions are narrow. The CVSS vector (AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:N/A:N) combines network reach and no authentication with HIGH attack complexity and REQUIRED user interaction, and Oracle explicitly labels it 'difficult to exploit.' No EPSS score, KEV listing, or POC was provided in the input, so exploitation probability signals are absent rather than low - this is a data gap, not evidence of safety. Critically, Oracle's own note restricts applicability to sandboxed Java Web Start applications and sandboxed Java applets that load untrusted code; this deployment mode has been deprecated and largely removed from modern browsers and JDKs, so the practically exploitable population is far smaller than the raw Java install base. Server-side Java (the dominant modern use) is explicitly NOT affected. Net: a real confidentiality flaw, but low operational urgency for most environments. Note also a tag conflict - the input tags this 'Authentication Bypass,' yet the vector and description describe information disclosure (C:H, I:N) with no auth-bypass semantics; verify tag accuracy with vendor. |
| Exploit ScenarioDerived | An attacker publishes a malicious Java Web Start application or applet on a website and lures a victim into launching it in a browser/JVM that still supports the deprecated applet/Web Start sandbox. When the victim runs the untrusted code, a flaw in the JGSS component lets the sandboxed code read confidential data it should not access. No public exploit code was identified in the provided data, and high attack complexity plus required user interaction make opportunistic mass exploitation unlikely. |
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Alert meAnalysisAIv1 – Oct 21, 2026
Unauthorized access to critical data in Oracle Java SE (8u503, 8u503-perf, 11.0.32.1, 17.0.20.1, 21.0.12.1, 25.0.4.1, and 27), Oracle GraalVM for JDK (17.0.20.1 and 21.0.12.1), and Oracle GraalVM Enterprise Edition (21.3.19.1.1) is possible through the JGSS component, but only in client deployments that run sandboxed Java Web Start applications or applets loading untrusted code; servers running only trusted administrator-installed code are explicitly not affected. Oracle describes the flaw as difficult to exploit (CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:N/A:N), requiring no privileges but needing a victim to interact with the malicious application, and no public exploit was identified at time of analysis. Despite the low real-world priority, organizations still using applet or Web Start sandboxes should apply the October 2026 CPU.
RemediationAI
Vendor-released patch: Oracle Critical Patch Update October 2026. Apply the update from https://www.oracle.com/security-alerts/cpuoct2026.html for the listed Java SE, GraalVM for JDK, and GraalVM Enterprise Edition releases, upgrading each affected JDK line to the CPU-patched build rather than remaining on 8u503, 11.0.32.1, 17.0.20.1, 21.0.12.1, 25.0.4.1, 27, or the listed GraalVM versions. Because exposure requires the Java sandbox, the most effective compensating control is to eliminate that attack surface: disable Java Web Start and browser applet execution (remove the Java browser plugin where still present, block .jnlp downloads, and set the deployment security level to Very High or disable untrusted JNLP in deployment.properties), accepting that legacy applet and Web Start applications will stop working. Restricting client Java to trusted, signed, allowlisted applications and blocking outbound fetches of untrusted JNLP or applet code reduces risk further; server deployments running only trusted code do not require emergency action but should still be patched for compliance.
Affected VersionsENISA
Affected Packages
Source: OSV (Open Source Vulnerabilities)
Affects your stack
Affects 3 packages in euvd
Checking this CVE against your own stacks and servers is part of the Basic plan and up.
Technical ContextAI · show details
The vulnerability resides in JGSS, the Java binding to the Generic Security Services API used for Kerberos and SPNEGO authentication, and is exposed when a sandboxed Java Web Start application or applet processes attacker-controlled code and relies on the Java sandbox for isolation. No CWE identifier was assigned in the supplied data, but the effect is a confidentiality breach (C:H) in which the sandbox's intended access restrictions can be bypassed, allowing reads of data otherwise inaccessible to the untrusted application. The CVSS vector confirms network access, high attack complexity, no privileges required, and user interaction; Oracle's own note limits scope to client deployments and excludes servers that load only trusted code, and modern JDK and browser releases have largely removed applet and Web Start support, further reducing exposure.
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Severity by source
AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:N/A:N
Network-reachable untrusted code with no auth (AV:N/PR:N) but victim must run it (UI:R) and it is hard to trigger (AC:H); impact is confidentiality-only disclosure (C:H, I:N, A:N).
Primary rating from Vendor (oracle).
CVSS VectorVendor: oracle
DescriptionCVE.org
Vulnerability in the Oracle Java SE, Oracle GraalVM for JDK, Oracle GraalVM Enterprise Edition product of Oracle Java SE (component: JGSS). 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 require human interaction from a person other than the attacker. Successful attacks of this vulnerability can result in unauthorized access to critical data or complete access to all Oracle Java SE, Oracle GraalVM for JDK, 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 5.3 (Confidentiality impacts). CVSS Vector: (CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:N/A:N).
Threat Intelligence Overview
How this decision was reached
The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.
What every action level means
SSVC AssessmentENISA
Priority Score
Attack Technique
Authentication bypass attacks exploit flaws in the verification mechanisms that control access to systems and applications.
Use-after-free vulnerabilities occur when a program continues to access memory through a pointer after that memory has been deallocated.
Memory corruption occurs when a program writes data beyond the boundaries of allocated memory regions or accesses memory in unintended ways, violating the integrity of the process's address space.
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EUVD-2026-106711
GHSA-pq5q-77c8-hwjv
NVD
CVE.org
EPSS
Exploit-DB