6.9
MEDIUM CVSS 4.0
CVE-2026-128345
ExcelJS through 4.4.0 ReDoS via slideFormula Shared Formula Translation
Description

ExcelJS through 4.4.0 contains a regular expression denial of service vulnerability in slideFormula in lib/utils/shared-formula.js when translating shared formulas to child cells. Attackers can supply a crafted spreadsheet with very long master formulas, such as runs of hyphens, causing quadratic regex backtracking that blocks the Node.js event loop.

INFO

Published Date :

Nov. 13, 2026, 10:18 a.m.

Last Modified :

Nov. 13, 2026, 10:18 a.m.

Remotely Exploit :

Yes !
Affected Products

The following products are affected by CVE-2026-128345 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

ID Vendor Product Action
1 Exceljs_project exceljs
CVSS Scores
The Common Vulnerability Scoring System is a standardized framework for assessing the severity of vulnerabilities in software and systems. We collect and displays CVSS scores from various sources for each CVE.
Score Version Severity Vector Exploitability Score Impact Score Source
CVSS 3.1 MEDIUM 83251b91-4cc7-4094-a5c7-464a1b83ea10
CVSS 3.1 MEDIUM MITRE-CVE
CVSS 3.1 MEDIUM [email protected]
CVSS 4.0 MEDIUM 83251b91-4cc7-4094-a5c7-464a1b83ea10
CVSS 4.0 MEDIUM [email protected]
Solution
Update ExcelJS to a version that mitigates regex-based denial-of-service.
  • Update ExcelJS to a fixed version.
  • Avoid processing untrusted spreadsheets.
  • Sanitize complex formulas before processing.
References to Advisories, Solutions, and Tools
CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-128345 is associated with the following CWEs:

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2026-128345 weaknesses.

We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).

Results are limited to the first 15 repositories due to potential performance issues.

The following list is the news that have been mention CVE-2026-128345 vulnerability anywhere in the article.

The following table lists the changes that have been made to the CVE-2026-128345 vulnerability over time.

Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.

  • New CVE Received by [email protected]

    Nov. 13, 2026

    Action Type Old Value New Value
    Added Description ExcelJS through 4.4.0 contains a regular expression denial of service vulnerability in slideFormula in lib/utils/shared-formula.js when translating shared formulas to child cells. Attackers can supply a crafted spreadsheet with very long master formulas, such as runs of hyphens, causing quadratic regex backtracking that blocks the Node.js event loop.
    Added CVSS V4.0 AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/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
    Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
    Added CWE CWE-1333
    Added Affected New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/128xxx/CVE-2026-128345.json">CVE-2026-128345</a>
    Added Reference https://github.com/exceljs/exceljs
    Added Reference https://github.com/exceljs/exceljs/blob/v4.4.0/lib/utils/shared-formula.js#L4-L12
    Added Reference https://github.com/mateocallec/exceljs-hardened/security/advisories/GHSA-pr65-54q8-vhqm
    Added Reference https://www.vulncheck.com/advisories/exceljs-through-4.4.0-redos-via-slideformula-shared-formula-translation
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.