Open Cascade Technology: Out-of-bounds Read
CVE-2026-42476 is a high-severity out-of-bounds read vulnerability in Open Cascade Technology from Opencascade, with a CVSS 3.1 base score of 7.1 out of 10. It can be exploited with local access to the system by an unauthenticated attacker, but only if a user takes part, for example by opening a link or file. Affected Open Cascade Technology versions: 7.9.3 and earlier; 8.0.0. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.11% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Check which version of Open Cascade Technology you run against the affected versions below, and install the vendor's latest release.
- Because the attack needs a user to take part, warn users about unexpected links and files related to this product until it is patched.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Opencascade | Open Cascade Technology | 7.9.3 and earlier; 8.0.0 | Not stated |
Version data comes from NVD's product matching. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- LocalThe attacker needs local access or must trick a user into running something.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- RequiredA user must take an action such as opening a file or link.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- NoneNothing can be modified.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 7.1 | High | NVD |
| CVSS 3.1 | 5.5 | Medium | CISA (ADP) |
Official description
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.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Out-of-bounds Read
The product reads data past the end, or before the beginning, of the intended buffer.
How developers prevent this class of flaw
- Use a language that provides appropriate memory abstractions.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Third-party and government advisories
- gist.github.com/sgInnora/dfba083d04906283e9c92aea78e2d94aThird Party Advisory
Other vulnerabilities in Open Cascade Technology
- 7.5 High severity
- 7.1 High severity
Recent Out-of-bounds Read vulnerabilities
- 8.1 High severity
- 8.8 High severity
- 7.1 High severity
- 7.3 High severity
- 7.1 High severity
- 7.1 High severity
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