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Open Cascade TechnologyApplication · Opencascade

CVE-2026-42477

HIGH · 7.1 CVSS v3.1 Published 2026-05-01
Fix available
A fix is available. Upgrade to after 7.9.3 or later.
See remediation →
74/100
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
A heap-based out-of-bounds read vulnerability in RWObj_Reader::read in the OBJ file parser in Open CASCADE Technology (OCCT) V8_0_0_rc5 allows user-assisted attackers to cause a denial of service or obtain sensitive information by persuading a victim to open a crafted OBJ file. The issue occurs because Standard_ReadLineBuffer::ReadLine() can return a 1-byte buffer for a minimal OBJ line, and RWObj_Reader::read() calls pushIndices(aLine + 2) without validating the buffer length.

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 · high confidence

Heap-based out-of-bounds read vulnerability in Open CASCADE Technology's OBJ file parser where RWObj_Reader::read() calls pushIndices(aLine + 2) without validating that the buffer returned by Standard_ReadLineBuffer::ReadLine() is at least 3 bytes, allowing attackers to read beyond buffer bounds via crafted OBJ files.

MitigationValidate buffer length is sufficient before accessing aLine + 2; avoid opening untrusted OBJ files until patch is applied.

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
High
Integrity
None
Availability
High

CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/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 version
    Check the installed version of Open CASCADE libraries (OCCT). Common locations: the assembly DLL version info, or query via the application's about dialog, or locate opencascade*.dll files and check their version properties. Compare against affected versions: <= 7.9.3 or = 8.0.0
    Affected if Installed version is 7.9.3 or earlier, or exactly 8.0.0
  2. Confirm RWObj module is in use
    Identify whether the application or workflow loads and uses the RWObj reader module for parsing OBJ 3D model files. This may be visible in application logs, module dependencies, or by observing that OBJ file import functionality is available
    Affected if The RWObj_Reader class is being invoked to parse OBJ files
  3. Assess source of OBJ files
    Determine whether the application processes OBJ files from untrusted or external sources. Review file input paths, upload mechanisms, or data pipelines that feed into the OBJ reader
    Affected if OBJ files from untrusted or external sources are being processed by the vulnerable reader

You are affected if your Open CASCADE version is 7.9.3 or earlier (or exactly 8.0.0) AND you parse OBJ files using RWObj_Reader, especially from untrusted sources.

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

Validate buffer length is sufficient before accessing aLine + 2; avoid opening untrusted OBJ files until patch is applied.

Recommended fix Moderate confidence

Open Cascade Technology 8.0.1 or later stable release

  1. 1. Identify the current Open Cascade Technology version in use by checking the product documentation or assembly metadata
  2. 2. Download the latest stable release of Open Cascade Technology from the official source (https://www.opencascade.com/)
  3. 3. Before deploying, test the new version in a staging environment to ensure compatibility with your application
  4. 4. Replace the existing OCCT libraries with the new version's libraries
  5. 5. Re-validate all OBJ file parsing functionality to confirm the vulnerability is resolved
  6. 6. Ensure any automated systems that process OBJ files are restarted to load the updated libraries
Caveat Newer OCCT versions may include API changes; review release notes for breaking changes before upgrading

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

Fix this in Open Cascade Technology Scoped from the published advisory
  • Consultation2.0 h
  • Implementation2.0 h
  • Testing3.0 h
  • Review / QA1.0 h
8.0 hours of engineering $1,390
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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-2026-42477 in production — separate from our analysis above.

No notes yet

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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