Skip to content
CVE Ledger
  • Newest CVEsPage
  • Recently added to KEVPage
  • Rising exploitation (EPSS)Page
  • Weekly digestPage
  • StatisticsPage
  • WatchlistPage
  • API docsPage
  • MCP serverPage
  • AboutPage
  • Data sourcesPage
  • Data statusPage
  • ChangelogPage
  • How it's builtPage
  • Support the projectPage

14 results

Back

CVE-2026-40296

PhpSpreadsheet vulnerable to XSS in HTML writer via custom number format codes

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.

Public exploit

An exploit or proof of concept is public: anyone can try it against an unpatched system. A reference of the record is tagged as an exploit. CISA's SSVC rates its exploitation: a proof of concept is public.

Show the exploits1

Timeline

  1. ID reserved

    By GitHub_M

  2. · 26 days later

    Published

  3. · 1 day later

    Record updated

Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.

Scores

CVSS scores of CVE-2026-40296, by who scored it
Scored byCVSSScoreVector
GitHub_MCNA (assigner)3.1Medium5.4CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
NVDNVD · Analyzed3.1Medium5.4CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
EPSS (exploitation in 30 days)
0.22% · top 87% of all CVEs (12 Nov 2026)
CISA SSVC
Exploitation: poc · Automatable: no · Technical impact: partial
Loading the EPSS history…

The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 5.4.

Affected products

  • PHPOffice · PhpSpreadsheet

    • affected >= 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 packages

From reviewed advisories of the GitHub Advisory Database.

References

References1

Sources

The same CVE in the primary databases and aggregators, to check against.

Badge for a README or a ticket

CVE-2026-40296 badge
[![CVE-2026-40296](https://cveledger.app/badge/CVE-2026-40296.svg)](https://cveledger.app/cve/CVE-2026-40296)

Record last updated .