Is CVE-2026-40902 actively exploited?

No active exploitation of CVE-2026-40902 has been confirmed so far. Continue monitoring, as exploit status can change.

Can CVE-2026-40902 be exploited remotely?

Yes. CVE-2026-40902 is exploitable remotely over the network (CVSS attack vector: Network).

What is the CVSS score of CVE-2026-40902?

CVE-2026-40902 has a CVSS score of 7.5 (HIGH).

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HIGH

CVE-2026-40902

CWE-770Published: May 12, 2026· Updated: May 14, 2026

7.5

CVSS v3.1

EPSS:0.04%probability of exploitation in 30 daysPercentile:12.1th

Official Description

PhpSpreadsheet is a pure PHP library for reading and writing spreadsheet files. Prior to 1.30.4, 2.1.16, 2.4.5, 3.10.5, and 5.7.0, the XLSX reader's ColumnAndRowAttributes::readRowAttributes() method reads row numbers from XML attributes without validating them against the spreadsheet maximum row limit (AddressRange::MAX_ROW = 1,048,576). An attacker can craft a minimal XLSX file (~1.6KB) containing a <row r="999999999"/> element that inflates cachedHighestRow to 999,999,999, causing any subsequent row iteration to attempt ~1 billion loop cycles and exhaust CPU resources. This vulnerability is fixed in 1.30.4, 2.1.16, 2.4.5, 3.10.5, and 5.7.0.

NVD Source

Technical Analysis

CVE-2026-40902 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.

A successful exploit results in availability disruption (denial of service), with a CVSS base score of 7.5.