CVE-2026-42477
Memory Safety in Opencascade Open Cascade Technology ≤ 7.9.3
Raw vector
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:HCVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.
Summary
CVE-2026-42477 is a high-severity Out-of-bounds Read (CWE-125) vulnerability in Opencascade Open Cascade Technology. Its CVSS base score is 7.1 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Privilege Escalation (T1068); ranked at the 1th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified map to SA-11 (Developer Testing and Evaluation) and SI-10 (Information Input Validation) — see the control section below for these in your framework.
Deeper analysis AI-assisted summary
Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.
CVE-2026-42477 is a heap-based out-of-bounds read vulnerability in the RWObj_Reader::read function of the OBJ file parser in Open CASCADE Technology (OCCT) V8_0_0_rc5. The issue stems from Standard_ReadLineBuffer::ReadLine() returning a 1-byte buffer for a minimal OBJ line, after which RWObj_Reader::read() invokes pushIndices(aLine + 2) without validating the buffer length. This flaw, classified under CWE-125, was published on 2026-05-01.
User-assisted attackers can exploit this vulnerability by persuading victims to open a crafted OBJ file, requiring local access (AV:L), low attack complexity (AC:L), no privileges (PR:N), and user interaction (UI:R). Successful exploitation can lead to denial of service (A:H) or disclosure of sensitive information (C:H), with no integrity impact (I:N) and no scope change (S:U), earning a CVSS v3.1 base score of 7.1.
Mitigation details are available in the referenced advisory at https://gist.github.com/sgInnora/dfba083d04906283e9c92aea78e2d94a.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-26600
Vulnerability Data
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…
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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.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
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V1.4.1
Mitigating Controls (NIST 800-53 r5) AI
Developer testing and evaluation directly finds out-of-bounds read flaws through static analysis, fuzzing, and dynamic bounds checks.
Input validation enforces bounds checking on data written to heap buffers, directly stopping the overflow condition from being introduced.
Secure engineering principles require bounds checking and memory-safe constructs that stop out-of-bounds reads from being introduced.
Process isolation confines the effects of an out-of-bounds read to the compromised process.
Memory-protection mechanisms limit the ability of a heap overflow to execute attacker-controlled code or corrupt adjacent structures.
Mitigating Controls (NIST CSF 2.0) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.
Secure-development practices directly require bounds checking and safe memory handling that prevent heap overflows.
Vulnerability scanning and recording can discover instances of out-of-bounds reads after code is deployed.
Routine patching replaces vulnerable code containing out-of-bounds read flaws.
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.
Security testing in development and acceptance includes fuzzing and static analysis that detect out-of-bounds read defects before release.
Logging can record evidence of an out-of-bounds read but does not prevent the weakness itself.
Secure development life cycle mandates input validation and bounds checking that directly prevent out-of-bounds reads.
Application security requirements include explicit bounds and memory-safety specifications that mitigate buffer over-reads.
Secure system architecture and engineering principles require memory-safe design patterns and runtime protections against out-of-bounds access.
Secure coding standards explicitly forbid unsafe pointer arithmetic and mandate bounds-checked reads, eliminating CWE-125.