CVE-2026-128341 json
ExcelJS through 4.4.0 Denial of Service via Oversized Data Validation sqref
published 29d ago modified 17h ago also EUVD-2026-125158 , GHSA-f689-fh93-2pm2
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
- 7.5
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.5%
- EPSS 0.5% chance of exploitation in 30 days, percentile 46%
- public exploits
- 0
- none known
Summary
ExcelJS through 4.4.0 contains a resource exhaustion vulnerability in data-validations-xform.js that allows attackers to exhaust CPU and memory by supplying unbounded sqref ranges. Attackers can provide a small crafted workbook with a sqref of A1:XFD1048576 to make xlsx.load() iterate billions of addresses, blocking the event loop and crashing the process with an uncatchable out-of-memory error.
Patch / fix
- npm exceljs-hardened 5.1.0
Is CVE-2026-128341 in your dependencies? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.
Check with FencerExploit prediction
0.54% chance of exploitation in the next 30 days, higher than 46% of all scored CVEs (FIRST EPSS, 2026-11-14).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 4.0 | 8.7 | 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 |
| CNA | 3.1 | 7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
| CNA | 4.0 | 8.7 | 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 |
| NVD | 3.1 | 7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| npm | exceljs-hardened | <=5.0.2 |
5.1.0 |
Affected products
- exceljs exceljs
Classification
- Weakness
-
- CWE-770 Allocation of Resources Without Limits or Throttling
References
-
github.com
/exceljs/exceljs
product
-
github.com
/mateocallec/exceljs-hardened/security/advisories/GHSA-f689-fh93-2pm2
third-party-advisory, advisory
-
github.com
/exceljs/exceljs/blob/v4.4.0/lib/xlsx/xform/sheet/data-validations-xform.js#L216-L227
technical-description
-
github.com
/exceljs/exceljs/issues/3093
issue-tracking
-
vulncheck.com
/advisories/exceljs-through-4.4.0-denial-of-service-via-oversized-data-validation-sqref
third-party-advisory
Sources
- CVE List CVE-2026-128341
- NVD CVE-2026-128341
- Maintainer advisory GHSA-f689-fh93-2pm2
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.