PhpSpreadsheet is a pure PHP library for reading and writing spreadsheet files. The HTML writer skips htmlspecialchars escaping when a cell's formatted value differs from the original value. When a cell has a custom number format containing the text placeholder @ along with any additional literal characters (for example ". @", "@ ", or "x@"), the formatter replaces @ with the cell value and adds the extra characters, causing the formatted value to differ from the original and bypassing HTML escaping entirely. An attacker who can control the cell value and number format of an uploaded spreadsheet that is later converted to HTML and displayed to other users can achieve stored cross-site scripting. This issue is fixed in versions 5.7.0, 3.10.5, 2.4.5, 2.1.16, and 1.30.4.

No CVSS v4.0

Attack Vector Network

Attack Complexity Low

Privileges Required Low

Scope Changed

Confidentiality Impact Low

Integrity Impact Low

Availability Impact None

User Interaction Required

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

No EPSS score available.

Key SSVC decision points have not yet been added.

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions
PHPOffice PhpSpreadsheet affected
Version Status Constraints
>= 4.0.0, <= 5.6.0 affected —
>= 3.3.0, <= 3.10.4 affected —
>= 2.2.0, <= 2.4.4 affected —
>= 2.0.0, <= 2.1.15 affected —
<= 1.30.3 affected —

No data.

No data.

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Advisories
Source ID Title
Github GHSA Github GHSA GHSA-hrmw-qprp-wgmc PhpSpreadsheet has XSS via number format code with @ text placeholder bypasses htmlspecialchars in HTML writer
Fixes

Solution

No solution given by the vendor.

Workaround

No workaround given by the vendor.

References
Link Providers
https://github.com/PHPOffice/PhpSpreadsheet/security/advisories/GHSA-hrmw-qprp-wgmc cve-icon cve-icon
History

Wed, 06 May 2026 23:00:00 +0000

Type Values Removed Values Added
First Time appeared Phpoffice
Phpoffice phpspreadsheet
Vendors & Products Phpoffice
Phpoffice phpspreadsheet

Wed, 06 May 2026 21:30:00 +0000

Type Values Removed Values Added
Description PhpSpreadsheet is a pure PHP library for reading and writing spreadsheet files. The HTML writer skips htmlspecialchars escaping when a cell's formatted value differs from the original value. When a cell has a custom number format containing the text placeholder @ along with any additional literal characters (for example ". @", "@ ", or "x@"), the formatter replaces @ with the cell value and adds the extra characters, causing the formatted value to differ from the original and bypassing HTML escaping entirely. An attacker who can control the cell value and number format of an uploaded spreadsheet that is later converted to HTML and displayed to other users can achieve stored cross-site scripting. This issue is fixed in versions 5.7.0, 3.10.5, 2.4.5, 2.1.16, and 1.30.4.
Title PhpSpreadsheet vulnerable to XSS in HTML writer via custom number format codes
Weaknesses CWE-79
References
Metrics cvssV3_1

{'score': 5.4, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N'}

Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-05-06T20:48:34.504Z

Reserved: 2026-04-10T20:22:44.035Z

Link: CVE-2026-40296

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-05-06T22:16:25.510

Modified: 2026-05-06T22:16:25.510

Link: CVE-2026-40296

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-05-06T22:45:13Z

Weaknesses