What’s Vulnerable › Vulnerabilities

CVE-2026-108358: PhpSpreadsheet: XmlScanner Bypass via ISO-2022 Escape Sequences Allows XXE and Denial of Service

• Severity: high (CVSS 8.8 v4.0)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.5% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-10-22 · updated 2026-10-23
• Weakness: CWE-611

Description

PhpSpreadsheet is a pure PHP library for reading and writing spreadsheet files. Prior to 1.30.7, 2.1.19, 2.4.8, 3.10.8, and 5.10.0, XmlScanner::scan in src/PhpSpreadsheet/Reader/Security/XmlScanner.php uses a DOCTYPE detection pattern that accounts for NUL-byte interleaving but not ISO-2022 escape sequences in XLSX XML parts. The escape sequences prevent the scanner from matching the declaration, and XML charset normalization then removes the escape bytes before parsing, exposing a valid DOCTYPE and entity definitions. Processing an attacker-controlled XLSX can therefore cause entity-expansion denial of service on supported PHP versions and can permit local file access or SSRF on PHP before 8.0 or when LIBXML_NOENT is enabled. This issue is fixed in versions 1.30.7, 2.1.19, 2.4.8, 3.10.8, and 5.10.0.

Affected products

• PHPOffice PhpSpreadsheet: before 1.30.7; from 2.0.0, < 2.1.19; from 2.2.0, < 2.4.8; from 3.3.0, < 3.10.8; from 4.0.0, < 5.10.0

References

• https://github.com/PHPOffice/PhpSpreadsheet/commit/299993894dce37aa3b64aa23e9a3f4bb77ab0e66
• https://github.com/PHPOffice/PhpSpreadsheet/commit/89f455c133e1a7e2d4abfadc43ce29eb7450d781
• https://github.com/PHPOffice/PhpSpreadsheet/commit/980b5c294493856f1a25754f1e8a1d2185b93738
• https://github.com/PHPOffice/PhpSpreadsheet/commit/9a0b48622ebfe93fa48cb9bc09ce57303bb07af9
• https://github.com/PHPOffice/PhpSpreadsheet/commit/da13f40e8760d599b0e8a296017d4b028b20e86c
• https://github.com/PHPOffice/PhpSpreadsheet/releases/tag/1.30.7
• https://github.com/PHPOffice/PhpSpreadsheet/releases/tag/2.1.19
• https://github.com/PHPOffice/PhpSpreadsheet/releases/tag/2.4.8
• https://github.com/PHPOffice/PhpSpreadsheet/releases/tag/3.10.8
• https://github.com/PHPOffice/PhpSpreadsheet/releases/tag/5.10.0
• https://github.com/PHPOffice/PhpSpreadsheet/security/advisories/GHSA-3x94-m842-937c

Get alerted when CVE-2026-108358 or the next vulnerability affects your stack