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CVE Record

CVE-2026-21945: Vulnerability in the Oracle Java SE, Oracle GraalVM for JDK, Oracle GraalVM Enterprise Edition product of O...

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 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).

HighCVSS 7.5Not KEV-listedUpdated
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Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

CVE-2026-21945 is a denial-of-service issue in specific Oracle Java SE and GraalVM releases. An unauthenticated network attacker can cause affected Java environments to hang or repeatedly crash. Oracle notes the risk is mainly for sandboxed Java clients running untrusted internet-sourced code, not typical servers running only administrator-installed trusted code.

Executive priority

Treat as high priority where legacy Java client technologies remain in use. For server-only Java environments running trusted code, prioritize verification and routine vendor patching rather than emergency response unless vendor guidance says otherwise.

Technical view

Oracle rates this CVSS 7.5, AV:N/AC:L/PR:N/UI:N, with high availability impact only. Affected releases include Java SE 8u471, 11.0.29, 17.0.17, 21.0.9, 25.0.1; GraalVM for JDK 17.0.17 and 21.0.9; and GraalVM Enterprise Edition 21.3.16. Listed weaknesses include CWE-295 and CWE-400.

Likely exposure

Highest exposure is client-side Java deployments that still run sandboxed Java Web Start applications or applets from untrusted sources. Standard server-side Java applications are less likely exposed when they load only trusted code installed by administrators, per Oracle’s note.

Exploitation context

The provided sources describe easy network exploitation and complete denial of service. They do not show CISA KEV listing or active exploitation evidence. No confidentiality or integrity impact is described in the CVSS vector.

Researcher notes

The key scoping detail is Oracle’s deployment note limiting applicability to sandboxed clients running untrusted code. The source bundle does not provide root-cause details, proof-of-concept status, or exact fixed version numbers beyond vendor advisory references.

Mitigation direction

  • Inventory Oracle Java SE and GraalVM versions against the affected version list.
  • Apply Oracle CPU January 2026 guidance or later vendor-provided fixes.
  • For Red Hat builds, follow the relevant RHSA advisories for your platform.
  • For Siemens environments, review SSA-032379 for product-specific guidance.
  • Reduce or disable sandboxed Java clients that run untrusted internet-sourced code.

Validation and detection

  • Confirm installed Java and GraalVM versions across endpoints and servers.
  • Identify Java Web Start, applet, or sandboxed-client usage in the environment.
  • Check whether affected runtimes load untrusted code from network sources.
  • Verify vendor advisory status for Oracle, Red Hat, and Siemens-managed packages.
  • Monitor affected systems for repeated Java hangs or crashes.
Prepared
Confidence
high
Sources
5

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.

cwe · low confidence lookup

CWE-295: Exact CWE lookup

Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.

Open ATT&CK lookup
cwe · low confidence lookup

CWE-400: Exact CWE lookup

Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.

Open ATT&CK lookup
cve · low confidence lookup

CVE-2026-21945 mapping review

Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.

Open ATT&CK lookup
Vulnerability profileCVE Program record
Severity
High
CVSS
7.5 (3.1)
Known Exploited
No
Published

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

2CVSS vectors
5Timeline events
3ADP providers
19Source links

SSVC decision data

CISA-ADPCISA Coordinator
Timestamp
Version
2.0.3
Exploitation: noneAutomatable: yesTechnical Impact: partial

CVSS vector scores

2 official scores

We collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.

ScoreVersionSeverityVectorExploitImpactSource
7.5CVSS 3.1HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H3.93.6oracle
7.5CVSS 3.1HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H3.93.6redhat-SADP

Vulnerability scoring details

Base CVSS 3.1 score

7.5High
CVSS 3.1 vector shape for CVE-2026-21945Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Privileges Required
NoneLowHigh
User Interaction
NoneRequired
Scope
ChangedUnchanged
Confidentiality Impact
HighLowNone
Integrity Impact
HighLowNone
Availability Impact
HighLowNone

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. ADP timelineredhat-SADP

    Reported to Red Hat.

  3. ADP timelineredhat-SADP

    Made public.

  4. CVE publishedCVE Program

    The CVE record was published.

  5. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

ADP provider summaries

CISA-ADPCISA ADP Vulnrichment
other:ssvc
siemens-SADPADP container
redhat-SADPopenjdk: Enhance Certificate Checking (Oracle CPU 2026-01)
other:Red Hat severity ratingcvssV3_1
  • 2026-01-15T12:05:58.026Z: Reported to Red Hat.
  • 2026-01-20T21:21:00.000Z: Made public.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
Oracle CorporationOracle Java SE8u471, 8u471-b50, 8u471-perf, 11.0.29, 17.0.17, 21.0.9, 25.0.1Listed
Oracle CorporationOracle GraalVM for JDK17.0.17, 21.0.9Listed
Oracle CorporationOracle GraalVM Enterprise Edition21.3.16Listed
Weakness

CWE details

CWE-295CWE-400

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.

CWE-295 · source CWE mapping

Improper Certificate Validation

Improper Certificate Validation represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.

Open CWE intelligenceSame-CWE CVEs
CWE-400 · source CWE mapping

Uncontrolled Resource Consumption

Uncontrolled Resource Consumption represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.

Open CWE intelligenceSame-CWE CVEs