Resource exhaustion in PhpSpreadsheet - CVE-2026-40863
Published: October 13, 2026
Vulnerability identifier: #VU154217
CSH Severity: Medium
CVSS v4: 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]
CVE-ID: CVE-2026-40863
CWE-ID: CWE-400
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to cause a denial of service.
The vulnerability exists due to unbounded processing of row indices in the SpreadsheetML XML reader when parsing SpreadsheetML XML input. A remote attacker can supply XML input containing an excessively large row index to cause a denial of service.
Affected software
PhpSpreadsheet
How to mitigate CVE-2026-40863
Install security update from vendor's website.
PhpSpreadsheet - addressed in versions 1.30.6, 2.1.16, 2.4.5, 3.10.5, 5.7.0