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CVE-2026-128345 ExcelJS through 4.4.0 ReDoS via slideFormula Shared Formula Translation

6.9 mediumEPSS 0.5%

Medium (6.9) in exceljs exceljs. EPSS 0.5% estimated probability of exploitation activity in the next 30 days.

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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.

Severity

CVSS 4.0

6.9 medium
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N

CVSS 3.1

5.3 medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
EPSS
0.5% estimated probability of exploitation activity in the next 30 days; 45th percentile. Scored 2026-11-13. A forecast for this CVE across the internet, not for your own systems.
CWE
CWE-1333 Inefficient Regular Expression Complexity
Published
Modified
Assigned by
VulnCheck (CNA)
NVD analysis
Awaiting analysis
Record from
the NVD, synced

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Affected

Versions

From the CNA's record in the CVE List.

ProductAffected
exceljsthrough 4.4.0

Attack patterns (CAPEC)

  • CAPEC-492 Regular Expression Exponential Blowup

The attack patterns MITRE's CAPEC relates to this record's weaknesses, as MITRE names them. Credits.

References

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