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Open Cascade TechnologyApplication · Opencascade

CVE-2026-42479

MEDIUM · 5.5 CVSS v3.1 Published 2026-05-01
Fix available
A fix is available. Upgrade to after 7.9.3 or later.
See remediation →
58/100
Remediation priority · Elevated
No privileges

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
An out-of-bounds read vulnerability in VrmlData_IndexedLineSet::TShape in the VRML parser in Open CASCADE Technology (OCCT) V8_0_0_rc5 allows attackers to cause a denial of service via a crafted VRML file. The issue occurs because coordIndex values from parsed input are used as direct array indices without validation against the size of the coordinate array during geometry processing.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · moderate confidence

An out-of-bounds read vulnerability exists in the VRML parser's VrmlData_IndexedLineSet::TShape function in Open CASCADE Technology V8_0_0_rc5. The coordIndex values from parsed VRML input are used directly as array indices without validation against the coordinate array's size, causing denial of service when processing crafted files with index values exceeding array bounds.

MitigationImplement bounds validation in TShape to ensure coordIndex values do not exceed the coordinate array size before array access; reject or clamp invalid indices and validate array bounds during VRML geometry processing.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Open Cascade TechnologyApplication
Affected:<= 7.9.3= 8.0.0

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Local
Complexity
Low
Privileges
None
User interaction
Required
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

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

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify Open CASCADE Technology installation
    Search for Open CASCADE libraries (libTKVRML, libOCCT, or OpenCASCADE*.dll/.so) on the system. Common locations: /usr/lib/opencascade, C:\Program Files\OpenCASCADE, or within application directories.
    Affected if Open CASCADE Technology libraries are present on the system
  2. Determine installed Open CASCADE version
    Run 'strings' on the library file or check version info on the DLL. Look for version strings like '7.9.3', '8.0.0', or check application metadata that bundles Open CASCADE.
    Affected if The version is 7.9.3 or lower, or exactly 8.0.0
  3. Verify VRML import module is in use
    Check if the application or system uses the VRML parser module (TKVRML component). Look for VRML file import functionality or check loaded modules for VRML-related libraries.
    Affected if The VRML parser component (TKVRML) is loaded or VRML file import feature is used
  4. Inspect VRML file processing paths
    If VRML files are processed, verify that coordIndex values are validated. This typically requires code review or checking if the application has implemented bounds checking in VrmlData_IndexedLineSet::TShape.
    Affected if VRML files with IndexedLineSet nodes are processed without bounds validation on coordIndex values relative to coordinate array size

A system is affected if Open CASCADE Technology version 7.9.3 or lower, or exactly 8.0.0, is installed and the VRML parser module processes IndexedLineSet geometry from untrusted VRML files.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to a release after 7.9.3
Interim mitigation

Implement bounds validation in TShape to ensure coordIndex values do not exceed the coordinate array size before array access; reject or clamp invalid indices and validate array bounds during VRML geometry processing.

Recommended fix Moderate confidence

Latest stable OCCT release (version 8.0.1 or later, if available)

  1. 1. Download the latest stable release of Open Cascade Technology (OCCT) from the official source (https://www.opencascade.com/ or the GitHub repository)
  2. 2. Verify that the release notes or changelog specifically mention a fix for the VRML parser out-of-bounds read vulnerability (CVE-2026-42479)
  3. 3. Back up your existing OCCT installation and any projects that depend on it
  4. 4. Install the new OCCT version following the standard build/installation procedures for your platform
  5. 5. Rebuild any projects that link against the OCCT libraries
  6. 6. Test your application to ensure the VRML parsing functionality works correctly with the new version
  7. 7. Verify that the crafted VRML file that triggered the vulnerability no longer causes a denial of service
Caveat Review the changelog between your current version and the new version for any API changes that may affect your application

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Open Cascade Technology Scoped from the published advisory
  • Consultation3.0 h
  • Implementation6.0 h
  • Testing4.0 h
  • Review / QA2.0 h
15.0 hours of engineering $2,640
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-42479 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data