CVE-2026-35453
MediumCVSS 5.4Exploitation Probability (EPSS)
Low risk10th percentile - higher than 10% of all known CVEs
Summary
In PhpSpreadsheet versions 1.30.3 and earlier, 2.0.0-2.1.15, 2.2.0-2.4.4, 3.3.0-3.10.4, and 4.0.0-5.6.0, the HTML Writer skips htmlspecialchars() escaping when a cell uses a custom number format containing @ with literals. An attacker controlling cell content can inject HTML and JavaScript.
Risk Assessment
An attacker can inject arbitrary script into the generated HTML report, leading to XSS and potential session hijacking of users viewing the report.
Recommendation
Update PhpSpreadsheet to version 1.30.4, 2.1.16, 2.4.5, 3.10.5, or 5.7.0.
Original NVD description (English source)
PhpSpreadsheet is a library for reading and writing spreadsheet files. In versions 1.30.3 and earlier, 2.0.0 through 2.1.15, 2.2.0 through 2.4.4, 3.3.0 through 3.10.4, and 4.0.0 through 5.6.0, the HTML Writer skips htmlspecialchars() output escaping when a cell uses a custom number format containing the @ text placeholder with additional literal text (e.g., @ "items"). The escaping is only applied when the formatted output strictly equals the original cell value. When the format code contains @ with quoted literal text, the formatter substitutes the raw cell value into the format string and returns early without invoking the escaping callback. An attacker who can control cell content in a spreadsheet processed by the HTML Writer can inject arbitrary HTML and JavaScript into the generated output. This issue has been fixed in versions 1.30.4, 2.1.16, 2.4.5, 3.10.5, and 5.7.0.