Cyber Resilience

CVE-2026-21945

DoS in Oracle Jdk 1.8.0 … 25.0.1

Published
20 January 2026
Modified
15 July 2026
Patch / advisory
CVSS Score v3.1 7.5
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS Score 0.0086 55th percentile
Risk Priority 59 floored blend · peak EPSS

Summary

CVE-2026-21945 is a high-severity Uncontrolled Resource Consumption (CWE-400) vulnerability in Oracle Jdk. Its CVSS base score is 7.5 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique OS Exhaustion Flood (T1499.001); ranked in the top 45% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified map to SC-17 (Public Key Infrastructure Certificates) and SC-5 (Denial-of-service Protection) — see the control section below for these in your framework.

Deeper analysis AI-assisted summary

Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.

CVE-2026-21945 is a vulnerability in the Security component of Oracle Java SE, Oracle GraalVM for JDK, and Oracle GraalVM Enterprise Edition. Affected versions include Oracle Java SE 8u471, 8u471-b50, 8u471-perf, 11.0.29, 17.0.17, 21.0.9, and 25.0.1; Oracle GraalVM for JDK 17.0.17 and 21.0.9; and Oracle GraalVM Enterprise Edition 21.3.16. Associated with CWE-400 (Uncontrolled Resource Consumption), it carries a CVSS 3.1 base score of 7.5 (High), with the vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H, reflecting high availability impact with no confidentiality or integrity effects.

An unauthenticated attacker with network access via multiple protocols can easily exploit this vulnerability to compromise the affected products. Successful exploitation results in the unauthorized ability to cause a hang or frequently repeatable crash, enabling complete denial-of-service (DoS) against the targeted Java instance. The vulnerability applies specifically to client-side Java deployments, such as those running sandboxed Java Web Start applications or sandboxed Java applets that load and run untrusted code from the internet while relying on the Java sandbox for security; it does not affect server-side deployments that load and run only trusted code.

The Oracle security advisory at https://www.oracle.com/security-alerts/cpujan2026.html details mitigation steps, including patches for the supported affected versions. Security practitioners should review this advisory for updated versions and apply them promptly to vulnerable deployments.

OWASP Top 10 for Web (2025)

EU & UK References

Vulnerability Data

Vulnerability in the Oracle Java SE, Oracle GraalVM for JDK, Oracle GraalVM Enterprise Edition product of Oracle Java SE (component: Security). Supported versions that are affected are Oracle Java SE: 8u471, 8u471-b50, 8u471-perf, 11.0.29, 17.0.17, 21.0.9, 25.0.1; Oracle GraalVM for…

more

JDK: 17.0.17 and 21.0.9; Oracle GraalVM Enterprise Edition: 21.3.16. 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 ability to cause a hang or frequently repeatable crash (complete DOS) of Oracle Java SE, Oracle GraalVM for JDK, Oracle GraalVM Enterprise Edition. 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 7.5 (Availability impacts). CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H).

CWE(s)

Related Threats

MITRE ATT&CK Enterprise Techniques

T1499.001 OS Exhaustion Flood Impact
Adversaries may launch a denial of service (DoS) attack targeting an endpoint's operating system (OS).
T1557 Adversary-in-the-Middle Credential Access
Adversaries may attempt to position themselves between two or more networked devices using an adversary-in-the-middle (AiTM) technique to support follow-on behaviors such as [Network Sniffing](https://attack.
T1498 Network Denial of Service Impact
Adversaries may perform Network Denial of Service (DoS) attacks to degrade or block the availability of targeted resources to users.
T1499 Endpoint Denial of Service Impact
Adversaries may perform Endpoint Denial of Service (DoS) attacks to degrade or block the availability of services to users.
T1499.002 Service Exhaustion Flood Impact
Adversaries may target the different network services provided by systems to conduct a denial of service (DoS).
T1499.003 Application Exhaustion Flood Impact
Adversaries may target resource intensive features of applications to cause a denial of service (DoS), denying availability to those applications.
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2026-47021Same product: Oracle Graalvm
CVE-2026-22021Same product: Oracle Graalvm
CVE-2026-34282Same product: Oracle Graalvm
CVE-2025-30752Same product: Oracle Graalvm For Jdk
CVE-2026-22003Same product: Oracle Graalvm
CVE-2026-22018Same product: Oracle Graalvm
CVE-2026-47057Same product: Oracle Jdk
CVE-2026-22007Same product: Oracle Graalvm
CVE-2025-61748Same product: Oracle Graalvm
CVE-2025-30754Same product: Oracle Graalvm

Affected Assets

oracle
graalvm
21.3.16
oracle
graalvm for jdk
17.0.17, 21.0.9
oracle
jdk
1.8.0, 11.0.29, 17.0.17, 21.0.9, 25.0.1
oracle
jre
1.8.0, 11.0.29, 17.0.17, 21.0.9, 25.0.1

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

Detect
Catch it (NIST detect / respond)

Harden
Shrink the surface (DISA STIG)
  • 12 hardening rules · 3 OS baselines
Validate
Prove the fix (OWASP ASVS)

Mitigating Controls (NIST 800-53 r5) AI

PKI certificate issuance and acquisition under an approved policy establishes the trusted roots and processes needed for correct validation.

SC-5 directly limits the effects of resource-exhaustion events that constitute uncontrolled consumption.

SC-6 enforces explicit allocation limits on resources, structurally preventing the weakness from occurring.

Protecting session authenticity depends on cryptographic mechanisms whose trust depends on correct certificate validation.

Process isolation confines resource consumption to separate domains, reducing blast radius without stopping the root flaw.

Requiring confidentiality and integrity protection of transmitted data drives use of properly validated certificates in protocols such as TLS.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.AA-03 mostly match
prevents

Certificate-based authentication of users/services/hardware directly depends on correct validation.

PR.DS-02 mostly match
prevents

Proper certificate validation is a core mechanism for protecting data-in-transit confidentiality and integrity.

PR.IR-04 mostly match
prevents

Explicitly requires monitoring and maintaining resource capacity, directly addressing uncontrolled consumption to preserve availability.

PR.PS-06 mostly match
prevents

Secure development practices explicitly include implementing correct certificate validation logic.

DE.CM-09 partial match
prevents

Continuous monitoring of computing resources can detect resource exhaustion but does not itself enforce allocation limits.

ID.RA-09 partial match
prevents

Assessing authenticity/integrity of acquired software often relies on code-signing certificate validation.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

finds

Resource-utilization monitoring and alerting on bottlenecks or overloads limits the impact of denial-of-service or resource-exhaustion attacks.

prevents

By continuously monitoring utilization, stress-testing peak loads, and maintaining documented plans to scale or throttle resources, the control directly limits an attacker’s ability to drive a system into uncontrolled resource exhaustion.

finds

Pre-agreed severity-based prioritization and resource allocation during incident triage reduce the likelihood that an attacker-induced resource exhaustion will overwhelm the organization before corrective action is taken.

mitigates

Business-continuity plans that include resource-management controls reduce the likelihood that an attacker can trigger uncontrolled resource consumption by forcing the system into a degraded or fallback state.

mitigates

Defining RTOs and capacity requirements for ICT services during business-impact analysis forces organizations to provision sufficient resources and throttling mechanisms, reducing the likelihood that an attacker can induce denial-of-service through uncontrolled resource consumption.

finds

Early notification of anomalous resource consumption or system malfunctions enables throttling or isolation before availability is lost.

Hardening callouts derived

Configuration rules from DISA STIG baselines that bear on weaknesses of the type cited by this CVE. Each rule is shown with the relationship its mapping actually records, against the CWE it was authored against. Derived via CVE→CWE over `controls_xwalks` (authoritative rows only; rows rated `none` are excluded).

Oracle Linux 8 (3 rules)
  • V-248574 YUM must be configured to prevent the installation of patches, service packs, device drivers, or OL 8 system components that have not been digitally signed using a certificate that is recognized and approved by the organization. prevents CWE-295
  • V-248531 OL 8, for PKI-based authentication, must validate certificates by constructing a certification path (which includes status information) to an accepted trust anchor. prevents CWE-295
  • V-248575 OL 8 must prevent the installation of software, patches, service packs, device drivers, or operating system components of local packages without verification they have been digitally signed using a certificate that is issued by a Certificate Authority (CA) that is recognized and approved by the organization. prevents CWE-295
RHEL 7 (2 rules)
  • V-204447 The Red Hat Enterprise Linux operating system must prevent the installation of software, patches, service packs, device drivers, or operating system components from a repository without verification they have been digitally signed using a certificate that is issued by a Certificate Authority (CA) that is recognized and approved by the organization. prevents CWE-295
  • V-204448 The Red Hat Enterprise Linux operating system must prevent the installation of software, patches, service packs, device drivers, or operating system components of local packages without verification they have been digitally signed using a certificate that is issued by a Certificate Authority (CA) that is recognized and approved by the organization. prevents CWE-295
RHEL 8 (2 rules)
  • V-230264 RHEL 8 must prevent the installation of software, patches, service packs, device drivers, or operating system components from a repository without verification they have been digitally signed using a certificate that is issued by a Certificate Authority (CA) that is recognized and approved by the organization. prevents CWE-295
  • V-230265 RHEL 8 must prevent the installation of software, patches, service packs, device drivers, or operating system components of local packages without verification they have been digitally signed using a certificate that is issued by a Certificate Authority (CA) that is recognized and approved by the organization. prevents CWE-295

References