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CVE-2026-78206— exceljs through 4.4.0 Uncontrolled Resource Consumption via Unbounded xlsx Decompression

Quick assessment

Affected
exceljs exceljs
Exploitation
Public or AI PoC available; prioritize validation
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

在 exceljs-hardened 5.0.0 版本之前，该库会将提供的 XLSX 归档文件中的所有条目解压到内存中，且对单个条目大小、总大小或压缩比没有任何限制。攻击者可以上传高度压缩的工作簿，这些工作簿在内存中膨胀至 GB 级别，从而耗尽可用资源并导致拒绝服务（DoS）。

CVSS 7.5 · High EPSS 0.45% · P37

Possible ATT&CK Techniques 1 AI

T1496 · Resource Hijacking

Affected Version Matrix 1

VendorProduct Version RangeStatus
exceljs exceljs ≤ 4.4.0 affected
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I. Basic Information for CVE-2026-78206

Vulnerability Information
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Vulnerability Title
exceljs through 4.4.0 Uncontrolled Resource Consumption via Unbounded xlsx Decompression
Source: CVE Program / CVE List V5
Vulnerability Description
exceljs-hardened before 5.0.0 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.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Source: CVE Program / CVE List V5
Vulnerability Type
对高度压缩数据的处理不恰当(数据放大攻击)
Source: CVE Program / CVE List V5

Affected Products

Vendor Product Affected Versions CPE Subscribe
exceljs exceljs 0 ~ 4.4.0 -

II. Public POCs for CVE-2026-78206

# POC Description Source Link Shenlong Link
AI-Generated POC Premium
Qwen3.6-35B-A3B · 8406 chars
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III. Intelligence Information for CVE-2026-78206

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Patches & Fixes for CVE-2026-78206 (1)

Vendor Advisories for CVE-2026-78206 (2)

Same Patch Batch · exceljs · 2026-08-24 · 4 CVEs total

CVE-2026-78207 9.4 CRITICAL exceljs through 4.4.0 Prototype Pollution via deepMerge Reached From Note Serialization
CVE-2026-78209 8.2 HIGH exceljs through 4.4.0 CSV Formula Injection via Unescaped Cell Values
CVE-2026-78208 7.5 HIGH exceljs through 4.4.0 Path Traversal via Unvalidated addImage filename

IV. Related Vulnerabilities

Same product: exceljs
Same vendor: exceljs
Same weakness: CWE-409

V. Comments for CVE-2026-78206

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