CVE-2024-45046Public exploitNetwork attack vector

Session takeover via unescaped spreadsheet font names

Published Aug 28, 2024 · Updated Aug 29, 2024

Cross-site scripting in PHPOffice PhpSpreadsheet before 1.29.1 and 2.0.0 allows remote authenticated users to execute JavaScript. Writer\Html::createCSSStyleFont places a spreadsheet-supplied font name into generated CSS without HTML escaping, letting a closing style tag introduce script markup. An attacker needs a path to submit a crafted spreadsheet, and a user must view the library's generated HTML; successful exploitation runs script in that user's web session.

CVSS severity4.8
Medium
EPSS probability0.42%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Cross-site scripting in PHPOffice PhpSpreadsheet before 1.29.1 and 2.0.0 allows remote authenticated users to execute JavaScript. Writer\Html::createCSSStyleFont places a spreadsheet-supplied font name into generated CSS without HTML escaping, letting a closing style tag introduce script markup. An attacker needs a path to submit a crafted spreadsheet, and a user must view the library's generated HTML; successful exploitation runs script in that user's web session.

The record

CVE
CVE-2024-45046
Published
Aug 28, 2024
Updated
Aug 29, 2024
Vendor
PHPOffice
Product
PhpSpreadsheet
Classifications
CWE-79, T1204.002
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 28, 2024CVE publishedPublication date reported by the CVE source.
  2. Aug 29, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <2.1.0
  2. Affected versionversion=< 2.1.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

PHPOffice · PhpSpreadsheetversion=0 <2.1.0; version=< 2.1.0

Published CVSS scores

4.8GitHub Advisory DatabaseCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N
5.4GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1204.002User Execution: Malicious File

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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