CVE-2026-78206

exceljs through 4.4.0 decompresses all entries from supplied xlsx archives into memory without limits on entry size, total size, or compression ratio. Attackers can upload highly compressed workbooks that expand to gigabytes in memory, exhausting available resources and causing denial of service.

CVSS v3 7.5 HIGH

7.5^/10

CVSS v3 : HIGH

Vector :

Exploitability : 3.9 / Impact : 3.6

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact NONE

Integrity Impact NONE

Availability Impact HIGH

Scope UNCHANGED

References

Link	Resource
https://github.com/exceljs/exceljs
https://github.com/exceljs/exceljs/blob/v4.4.0/lib/xlsx/xlsx.js#L257-L281
https://github.com/mateocallec/exceljs-hardened/security/advisories/GHSA-7cvf-3r55-r39q
https://www.vulncheck.com/advisories/exceljs-through-uncontrolled-resource-consumption-via-unbounded-xlsx-decompression

Configurations

No configuration.

History

14 Oct 2026, 13:10

Type	Values Removed	Values Added
Summary		(es) exceljs-hardened anterior a la versión 5.0.0 descomprime todas las entradas de los archivos xlsx suministrados en memoria sin límites en el tamaño de la entrada, el tamaño total o la relación de compresión. Los atacantes pueden cargar libros de trabajo altamente comprimidos que se expanden a gigabytes en memoria, agotando los recursos disponibles y causando denegación de servicio.

Information

Published : 2026-08-24 01:16

Updated : 2026-10-14 13:10

NVD link : CVE-2026-78206

Mitre link : CVE-2026-78206

CVE.ORG link : CVE-2026-78206

JSON object : View

Products Affected

No product.

CWE

CWE-409

Improper Handling of Highly Compressed Data (Data Amplification)

{"id": "CVE-2026-78206", "cveTags": [], "metrics": {"ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-78206", "role": "CISA Coordinator", "options": [{"exploitation": "none"}, {"automatable": "yes"}, {"technicalImpact": "partial"}], "version": "2.0.3", "timestamp": "2026-08-26T18:09:41.294502Z"}}], "cvssMetricV31": [{"type": "Secondary", "source": "disclosure@vulncheck.com", "cvssData": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 7.5, "attackVector": "NETWORK", "baseSeverity": "HIGH", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H", "integrityImpact": "NONE", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "HIGH", "privilegesRequired": "NONE", "confidentialityImpact": "NONE"}, "impactScore": 3.6, "exploitabilityScore": 3.9}], "cvssMetricV40": [{"type": "Secondary", "source": "disclosure@vulncheck.com", "cvssData": {"Safety": "NOT_DEFINED", "version": "4.0", "Recovery": "NOT_DEFINED", "baseScore": 8.7, "Automatable": "NOT_DEFINED", "attackVector": "NETWORK", "baseSeverity": "HIGH", "valueDensity": "NOT_DEFINED", "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/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", "exploitMaturity": "NOT_DEFINED", "providerUrgency": "NOT_DEFINED", "userInteraction": "NONE", "attackComplexity": "LOW", "attackRequirements": "NONE", "privilegesRequired": "NONE", "subIntegrityImpact": "NONE", "vulnIntegrityImpact": "NONE", "integrityRequirement": "NOT_DEFINED", "modifiedAttackVector": "NOT_DEFINED", "subAvailabilityImpact": "NONE", "vulnAvailabilityImpact": "HIGH", "availabilityRequirement": "NOT_DEFINED", "modifiedUserInteraction": "NOT_DEFINED", "modifiedAttackComplexity": "NOT_DEFINED", "subConfidentialityImpact": "NONE", "vulnConfidentialityImpact": "NONE", "confidentialityRequirement": "NOT_DEFINED", "modifiedAttackRequirements": "NOT_DEFINED", "modifiedPrivilegesRequired": "NOT_DEFINED", "modifiedSubIntegrityImpact": "NOT_DEFINED", "modifiedVulnIntegrityImpact": "NOT_DEFINED", "vulnerabilityResponseEffort": "NOT_DEFINED", "modifiedSubAvailabilityImpact": "NOT_DEFINED", "modifiedVulnAvailabilityImpact": "NOT_DEFINED", "modifiedSubConfidentialityImpact": "NOT_DEFINED", "modifiedVulnConfidentialityImpact": "NOT_DEFINED"}}]}, "affected": [{"source": "disclosure@vulncheck.com", "affectedData": [{"vendor": "exceljs", "product": "exceljs", "versions": [{"status": "affected", "version": "0", "versionType": "semver", "lessThanOrEqual": "4.4.0"}], "packageURL": "pkg:npm/exceljs", "packageName": "exceljs", "collectionURL": "https://www.npmjs.com/package/exceljs", "defaultStatus": "unaffected"}]}], "published": "2026-08-24T01:16:57.973", "references": [{"url": "https://github.com/exceljs/exceljs", "source": "disclosure@vulncheck.com"}, {"url": "https://github.com/exceljs/exceljs/blob/v4.4.0/lib/xlsx/xlsx.js#L257-L281", "source": "disclosure@vulncheck.com"}, {"url": "https://github.com/mateocallec/exceljs-hardened/security/advisories/GHSA-7cvf-3r55-r39q", "source": "disclosure@vulncheck.com"}, {"url": "https://www.vulncheck.com/advisories/exceljs-through-uncontrolled-resource-consumption-via-unbounded-xlsx-decompression", "source": "disclosure@vulncheck.com"}], "vulnStatus": "Deferred", "weaknesses": [{"type": "Secondary", "source": "disclosure@vulncheck.com", "description": [{"lang": "en", "value": "CWE-409"}]}], "descriptions": [{"lang": "en", "value": "exceljs through 4.4.0 decompresses all entries from supplied xlsx archives into memory without limits on entry size, total size, or compression ratio. Attackers can upload highly compressed workbooks that expand to gigabytes in memory, exhausting available resources and causing denial of service."}, {"lang": "es", "value": "exceljs-hardened anterior a la versi\u00f3n 5.0.0 descomprime todas las entradas de los archivos xlsx suministrados en memoria sin l\u00edmites en el tama\u00f1o de la entrada, el tama\u00f1o total o la relaci\u00f3n de compresi\u00f3n. Los atacantes pueden cargar libros de trabajo altamente comprimidos que se expanden a gigabytes en memoria, agotando los recursos disponibles y causando denegaci\u00f3n de servicio."}], "lastModified": "2026-10-14T13:10:00.187", "sourceIdentifier": "disclosure@vulncheck.com"}