# CVE-2026-42476: Two heap-based out-of-bounds read vulnerabilities in the STL ASCII file parser in Open CASCADE Technology (OCCT)…

Source: https://junglewise.ai/threats/cve-2026-42476-two-heap-based-out-of-bounds-read-vulnerabilities-in-the-stl  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-05-01  
License: CC BY 4.0 with a link back

CVE-2026-42476 · Severity: high · CVSS 7.1 · Published 2026-05-01

Two heap-based out-of-bounds read vulnerabilities in the STL ASCII file parser in Open CASCADE Technology (OCCT) V8_0_0_rc5 exist in RWStl_Reader::ReadAscii because buffers returned by Standard_ReadLineBuffer::ReadLine() are not properly length-validated before strncasecmp or direct byte access. User-assisted attackers can trigger these issues by persuading a victim to open a crafted STL file with extremely short lines, resulting in a denial of service or possible information disclosure.

Technologies: [Opencascade Open Cascade Technology](https://junglewise.ai/threats/technologies/open-cascade-technology). Vendors: [Opencascade](https://junglewise.ai/threats/vendors/opencascade).

## Quick answers

**Is CVE-2026-42476 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-42476 being exploited in the wild.

**How severe is CVE-2026-42476?** High severity, with a CVSS score of 7.1, published 1 May 2026.

**Which products and versions are affected?** Opencascade Open Cascade Technology. The advisory does not name versions.

**Is there a fix for CVE-2026-42476?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**Am I affected by CVE-2026-42476?** Check whether you run Opencascade Open Cascade Technology. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Affected products

- Opencascade Open Cascade Technology

## Related threats

- [An out-of-bounds read vulnerability in VrmlData_IndexedLineSet::TShape in the VRML parser in Open CASCADE Technology…](https://junglewise.ai/threats/cve-2026-42479-an-out-of-bounds-read-vulnerability-in-vrmldata-indexedlineset)