CVE-2024-43407Network attack vector

Reflected XSS via backend GeSHi response

Published Aug 21, 2024 · Updated Aug 21, 2024

Reflected XSS in CKSource CKEditor 4 before 4.25.0-lts allows remote attackers to execute script in a user's browser through GeSHi. The PHP colorize.php adapter passes attacker-controlled JSON fields into the unmaintained GeSHi parser and returns its generated markup without an intervening sanitizer. Exposure requires the optional Code Snippet GeSHi plugin, a backend PHP endpoint, and a user who opens the crafted response; successful exploitation runs script in that browser origin.

CVSS severity5.3
Medium
EPSS probability0.45%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Reflected XSS in CKSource CKEditor 4 before 4.25.0-lts allows remote attackers to execute script in a user's browser through GeSHi. The PHP colorize.php adapter passes attacker-controlled JSON fields into the unmaintained GeSHi parser and returns its generated markup without an intervening sanitizer. Exposure requires the optional Code Snippet GeSHi plugin, a backend PHP endpoint, and a user who opens the crafted response; successful exploitation runs script in that browser origin.

The record

CVE
CVE-2024-43407
Published
Aug 21, 2024
Updated
Aug 21, 2024
Vendor
CKSource
Product
CKEditor 4
Classifications
CWE-79, T1189
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 21, 2024CVE publishedPublication date reported by the CVE source.
  2. Aug 21, 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=< 4.25.0-lts

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

CKSource · CKEditor 4version=< 4.25.0-lts

Published CVSS scores

5.3GitHubCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N
6.1GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:N/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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

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
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1189Drive-by Compromise

Public exploit references

No public exploit references are available in this record.

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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