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TI-2026-27584 Aliases CVE-2026-35453GHSA-6wpp-88cp-7q68

PhpSpreadsheet XSS via number format text substitution in HTML Writer

Priority MEDIUM 55CWE-79Published · Updated

Key facts

Attack vector
Network
Privileges required
Low
User interaction
Active
Attack complexity
Low
Attack requirements
None
Impact type
Cross-site scripting
Confidentiality · integrity · availability
None · None · None
Fix status
Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA and GitHub. Impact type from CWE-79.

Summary

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.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00202 10th percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by NVD
Fix Fixed phpoffice/phpspreadsheet (Packagist): 5.7.0, 3.10.5, 2.4.5 +2

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
Poc
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
PHPOfficePhpSpreadsheet4.0.0 – 5.6.0; 3.3.0 – 3.10.4; 2.2.0 – 2.4.4; 2.0.0 – 2.1.15; up to 1.30.3—No fix listedCNA
—phpoffice/phpspreadsheet (Packagist)4.0.0 to before 5.7.05.7.0Patch availableGHSA-6wpp-88cp-7q68
—phpoffice/phpspreadsheet (Packagist)3.3.0 to before 3.10.53.10.5Patch availableGHSA-6wpp-88cp-7q68
—phpoffice/phpspreadsheet (Packagist)2.2.0 to before 2.4.52.4.5Patch availableGHSA-6wpp-88cp-7q68
—phpoffice/phpspreadsheet (Packagist)2.0.0 to before 2.1.162.1.16Patch availableGHSA-6wpp-88cp-7q68
—phpoffice/phpspreadsheet (Packagist)before 1.30.41.30.4Patch availableGHSA-6wpp-88cp-7q68
  • PhpSpreadsheet VendorPHPOffice Affected 4.0.0 – 5.6.0; 3.3.0 – 3.10.4; 2.2.0 – 2.4.4; 2.0.0 – 2.1.15; up to 1.30.3 Fixed in — No fix listed CNA
  • phpoffice/phpspreadsheet (Packagist) Vendor— Affected 4.0.0 to before 5.7.0 Fixed in 5.7.0 Patch available GHSA-6wpp-88cp-7q68
  • phpoffice/phpspreadsheet (Packagist) Vendor— Affected 3.3.0 to before 3.10.5 Fixed in 3.10.5 Patch available GHSA-6wpp-88cp-7q68
  • phpoffice/phpspreadsheet (Packagist) Vendor— Affected 2.2.0 to before 2.4.5 Fixed in 2.4.5 Patch available GHSA-6wpp-88cp-7q68
  • phpoffice/phpspreadsheet (Packagist) Vendor— Affected 2.0.0 to before 2.1.16 Fixed in 2.1.16 Patch available GHSA-6wpp-88cp-7q68
  • phpoffice/phpspreadsheet (Packagist) Vendor— Affected before 1.30.4 Fixed in 1.30.4 Patch available GHSA-6wpp-88cp-7q68

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:phpoffice:phpspreadsheet:*:*:*:*:*:*:*:*before 1.30.4; 2.0.0 to before 2.1.16; 2.2.0 to before 2.4.5; 3.3.0 to before 3.10.5; 4.0.0 to before 5.7.0VulnerablePHPOffice
  • cpe:2.3:a:phpoffice:phpspreadsheet:*:*:*:*:*:*:*:* Versions before 1.30.4; 2.0.0 to before 2.1.16; 2.2.0 to before 2.4.5; 3.3.0 to before 3.10.5; 4.0.0 to before 5.7.0 Vulnerable ·PHPOffice

Remediation

  • Fix · GHSA-6wpp-88cp-7q68 phpoffice/phpspreadsheet (Packagist) Fixed in 5.7.0 Advisory →
  • Fix · GHSA-6wpp-88cp-7q68 phpoffice/phpspreadsheet (Packagist) Fixed in 3.10.5 Advisory →
  • Fix · GHSA-6wpp-88cp-7q68 phpoffice/phpspreadsheet (Packagist) Fixed in 2.4.5 Advisory →
  • Fix · GHSA-6wpp-88cp-7q68 phpoffice/phpspreadsheet (Packagist) Fixed in 2.1.16 Advisory →
  • Fix · GHSA-6wpp-88cp-7q68 phpoffice/phpspreadsheet (Packagist) Fixed in 1.30.4 Advisory →

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-35453
  2. 2026-10-03 Alias added: GHSA-6wpp-88cp-7q68

References

Exploit 1

Advisory 1

Other 1

  • TI-2026-26406 PhpSpreadsheet SSRF and RCE via PHP stream wrappers in IOFactory::load CVSS 4.0CRITICAL 9.2
  • TI-2024-37339 PhpSpreadsheet vulnerable to unauthorized reflected XSS in Currency.php file CVSS 4.0HIGH 8.3
  • TI-2024-37338 PhpSpreadsheet allows unauthorized reflected XSS in `Convert-Online.php` file CVSS 4.0HIGH 8.3
  • TI-2024-37325 PhpSpreadsheet vulnerable to unauthorized reflected XSS in the Accounting.php file CVSS 4.0HIGH 8.3
  • TI-2024-37324 PhpSpreadsheet vulnerable to unauthorized reflected XSS in the constructor of the Downloader class CVSS 4.0HIGH 8.3
  • TI-2024-30160 XML External Entity Reference (XXE) in PHPSpreadsheet CVSS 3.1HIGH 8.8
See all 24 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences