CVE-2026-78208Network attack vector

Arbitrary file read via unvalidated image filename

Published Aug 24, 2026 · Updated Aug 24, 2026

Path traversal in ExcelJS 4.4.0 and earlier allows remote attackers to read process-accessible files through crafted image paths. Workbook.addImage stores an unvalidated filename, and XLSX.addMedia passes it directly to fs.readFile before embedding the data in a workbook. Exploitation requires a consuming application to supply attacker-influenced filenames; disclosure is limited to files readable by its Node.js process.

CVSS severity8.7
High
EPSS probability0.37%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Path traversal in ExcelJS 4.4.0 and earlier allows remote attackers to read process-accessible files through crafted image paths. Workbook.addImage stores an unvalidated filename, and XLSX.addMedia passes it directly to fs.readFile before embedding the data in a workbook. Exploitation requires a consuming application to supply attacker-influenced filenames; disclosure is limited to files readable by its Node.js process.

The record

CVE
CVE-2026-78208
Published
Aug 24, 2026
Updated
Aug 24, 2026
Vendor
ExcelJS
Product
ExcelJS
Classifications
CWE-73, CWE-22, T1005
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 24, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 24, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <=4.4.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

ExcelJS · ExcelJSversion=0 <=4.4.0

Published CVSS scores

7.5VulnCheckCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
8.7VulnCheckCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-73External Control of File Name or Path
CWE-22Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
T1005Data from Local System

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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