CVE-2026-78209 json
exceljs through 4.4.0 CSV Formula Injection via Unescaped Cell Values
published 2mo ago modified 3d ago also EUVD-2026-64684 , GHSA-9wxc-4rhw-hfrw
Unreviewed: the maintainers' own advisory
Published by the maintainers on their GitHub repository mateocallec/exceljs-hardened. GitHub has not reviewed it into the GitHub Advisory Database, so the affected packages and versions are the maintainers' word. Read the full advisory on GitHub.
- cvss
- 8.2
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.4%
- EPSS 0.4% chance of exploitation in 30 days, percentile 35%
- public exploits
- 0
- none known
Summary
exceljs through 4.4.0 fails to neutralize leading equals, plus, minus, or at signs in cell values written to CSV output. Attackers who can influence exported cell values can inject formulas that execute when the CSV file is opened in a spreadsheet application, potentially exfiltrating data or performing other malicious actions.
Patch / fix
- npm exceljs-hardened 5.0.0
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- Exploitation
- none
- Automatable
- no
- Technical impact
- partial
- Assessed
- 2mo ago
Exploit prediction
0.41% chance of exploitation in the next 30 days, higher than 35% of all scored CVEs (FIRST EPSS, 2026-11-11).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 4.0 | 8.4 | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:L/VA:N/SC:H/SI:L/SA:N |
| CNA | 3.1 | 8.2 | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:L/A:N |
| CNA | 4.0 | 8.4 | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:L/VA:N/SC:H/SI:L/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 |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| npm | exceljs-hardened | <=4.4.0 |
5.0.0 |
Affected products
- exceljs exceljs
Classification
- Weakness
-
- CWE-1236 Improper Neutralization of Formula Elements in a CSV File
References
-
github.com
/mateocallec/exceljs-hardened/security/advisories/GHSA-9wxc-4rhw-hfrw
third-party-advisory, vendor-advisory, advisory
-
github.com
/exceljs/exceljs
product
-
github.com
/exceljs/exceljs/blob/v4.4.0/lib/csv/csv.js#L109-L182
technical-description
-
vulncheck.com
/advisories/exceljs-through-csv-formula-injection-via-unescaped-cell-values
third-party-advisory
Sources
- CVE List CVE-2026-78209
- NVD CVE-2026-78209
- Maintainer advisory GHSA-9wxc-4rhw-hfrw
Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.
The maintainers of mateocallec/exceljs-hardened published their own advisory on GitHub. Reviewed sources take precedence over it.
CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.