exceljs-hardened before 5.0.0 decompresses all entries from supplied xlsx archives into memory without limits on entry size, total size, or… (CVE-2026-78206)
A vulnerability in exceljs-hardened versions before 5.0.0 allows decompression of all entries from supplied XLSX archives into memory without limits on entry size, total size, or compression ratio. This can enable attackers to upload highly compressed workbooks that expand to gigabytes in memory, exhausting system resources and causing a denial of service condition.
AI Analysis
Technical Summary
The exceljs-hardened library versions prior to 5.0.0 do not impose limits on the size or compression ratio of entries when decompressing XLSX archive files. An attacker can exploit this by uploading a workbook that decompresses into gigabytes of data in memory, causing exhaustion of system resources and resulting in a denial of service condition. This vulnerability is tracked as CVE-2026-78206 and is associated with CWE-409 (Resource Exhaustion).
Potential Impact
Exploitation of this vulnerability can cause denial of service by exhausting available memory resources on the system processing the XLSX files. There is no impact on confidentiality or integrity reported.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. No official fix or patch links are currently provided. Until a fix is available, users should consider restricting or validating XLSX file inputs to prevent processing of untrusted or excessively large compressed archives.
exceljs-hardened before 5.0.0 decompresses all entries from supplied xlsx archives into memory without limits on entry size, total size, or… (CVE-2026-78206)
Description
A vulnerability in exceljs-hardened versions before 5.0.0 allows decompression of all entries from supplied XLSX archives into memory without limits on entry size, total size, or compression ratio. This can enable attackers to upload highly compressed workbooks that expand to gigabytes in memory, exhausting system resources and causing a denial of service condition.
CVSS v3.1
Score 7.5high
Affected software
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Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The exceljs-hardened library versions prior to 5.0.0 do not impose limits on the size or compression ratio of entries when decompressing XLSX archive files. An attacker can exploit this by uploading a workbook that decompresses into gigabytes of data in memory, causing exhaustion of system resources and resulting in a denial of service condition. This vulnerability is tracked as CVE-2026-78206 and is associated with CWE-409 (Resource Exhaustion).
Potential Impact
Exploitation of this vulnerability can cause denial of service by exhausting available memory resources on the system processing the XLSX files. There is no impact on confidentiality or integrity reported.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. No official fix or patch links are currently provided. Until a fix is available, users should consider restricting or validating XLSX file inputs to prevent processing of untrusted or excessively large compressed archives.
Technical Details
- Gcve Source
- db.gcve.eu
- Osv Id
- GHSA-r7gv-hxj8-94c4
- Osv Schema Version
- 1.4.0
- Aliases
- ["CVE-2026-78206"]
- Ecosystems
- []
- Database Specific Severity
- HIGH
- Cvss Version
- 3.1
Threat ID: 6a8c4c77acd9273b499c0edf
Added to database: 08/24/2026, 13:51:51 UTC
Last enriched: 08/24/2026, 14:31:15 UTC
Last updated: 08/25/2026, 00:45:29 UTC
Views: 9
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