CVE-2026-91410 in Java SE
Summary
by MITRE • 10/21/2026
Vulnerability in Oracle Java SE (component: Libraries). 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; 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. Successful attacks of this vulnerability can result in unauthorized ability to cause a partial denial of service (partial DOS) of Oracle Java SE. 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 5.3 (Availability impacts). CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L).
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Analysis
by VulDB Data Team • 10/21/2026
The identified vulnerability resides within the Libraries component of Oracle Java SE and its associated distributions, including specific supported versions such as 8u503, 11.0.32.1, 17.0.20.1, 21.0.12.1, and 25.0.4.1, alongside Oracle GraalVM variants at similar release levels. This flaw represents a significant availability risk for environments relying on these Java runtimes, particularly those executing untrusted code within sandboxed contexts like Java Web Start applications or applets that fetch resources from external sources. The core technical issue involves an easily exploitable condition triggered when the specified APIs process data supplied via web services or other network-accessible protocols. Because the vulnerability allows for unauthorized denial of service conditions without requiring authentication, it poses a direct threat to the stability and continuity of Java-based enterprise applications and client-side deployments that depend on these library functions for normal operation.
From an operational perspective, this vulnerability enables unauthenticated attackers with network access to cause partial denials of service against Oracle Java SE installations. The attack vector is characterized by low complexity and does not require user interaction or prior authentication privileges, making it highly accessible to malicious actors scanning the internet for vulnerable endpoints. When exploited, typically through APIs that consume external data inputs, the flaw leads to resource exhaustion or state corruption within the JVM process, resulting in degraded performance or complete unavailability of the Java service. This impact aligns with CWE-400, which describes conditions where resources are not properly controlled, leading to denial of service scenarios. The ability to disrupt services remotely underscores the critical nature of this flaw for any organization running public-facing Java applications or internal systems that process external data streams using the affected library components.
The security implications extend beyond simple availability loss, as partial denials of service can mask other malicious activities or create opportunities for further exploitation in complex application stacks where cascading failures might occur. The vulnerability affects both server-side deployments and client-side sandboxed environments, meaning that organizations must assess their exposure across all Java runtime instances. For clients running sandboxed applications, the risk is heightened because these apps often rely on the Java security model to isolate untrusted code; however, this specific flaw in the underlying libraries can bypass or overwhelm those safeguards when processing malformed or excessively demanding inputs from network sources. This scenario reflects ATT&CK technique T1499, Endpoint Denial of Service, where an adversary disrupts access to an asset by consuming resources such as CPU, memory, or disk space through inefficient code execution patterns facilitated by the library flaw.
Mitigation strategies must prioritize immediate patching to the latest available updates for all affected Oracle Java SE and GraalVM versions listed in the advisory. Organizations should audit their infrastructure to identify any systems running vulnerable builds, particularly those exposed to network traffic via web services or APIs that interact with the compromised libraries. In addition to updating software, implementing strict input validation and rate limiting on external-facing endpoints can help mitigate the impact of such attacks by preventing the delivery of malicious payloads before they reach the vulnerable code paths. Security teams should also monitor for anomalous resource usage patterns indicative of denial-of-service attempts targeting Java processes. Given that this vulnerability impacts availability rather than confidentiality or integrity, maintaining robust monitoring and incident response procedures is essential to quickly detect and recover from any exploitation events while ensuring minimal disruption to business operations dependent on these Java components.