Dashboard / CVE-2026-40296

CVE-2026-40296

MEDIUM
MEDIUM Priority: 0.01 BB Relevance: 51/100
Published: 2026-05-06 Modified: 2026-10-26 First seen: 2026-10-29 Status: active

Attack Surface

Network Low Complexity Scope Change

CVSS Vector Breakdown

AV: Network
AC: Low
PR: Low
UI: Required
S: Changed
C: Low
I: Low
A: None

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.

Weakness Classification (1)

Affected Software (5)

VendorProductVersion
phpoffice phpspreadsheet < 1.30.4
phpoffice phpspreadsheet 2.0.0 – 2.1.16
phpoffice phpspreadsheet 2.2.0 – 2.4.5
phpoffice phpspreadsheet 3.3.0 – 3.10.5
phpoffice phpspreadsheet 4.0.0 – 5.7.0

References & Advisories (1)

Bug Bounty Relevance

51 / 100
✓ Network accessible
✓ Low complexity

CVSS Score

5.4 / 10.0 v3.1
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N

EPSS — Exploitation Probability

0.22%
Raw Score 0.002250
Percentile 13.2%
Date 2026-10-29

EPSS Trend

2026-10-29
0.00225
2026-10-28
0.00225

Intelligence Sources

nvd ref →

External Links