CVE-2023-53891Public exploitNetwork attack vector

Stored XSS via unsanitized page content

Published Dec 15, 2025 · Updated Dec 15, 2025

Stored XSS in BlackCat CMS 1.4 allows remote authenticated users to execute scripts in other users' browsers via page content. The backend/pages/modify.php workflow stores attacker-supplied HTML with an onerror handler, and the preview route renders it without neutralizing the handler. An account with page-modification permission and a victim viewing the modified page are required, enabling script execution in the victim's CMS origin.

CVSS severity5.1
Medium
EPSS probability0.24%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stored XSS in BlackCat CMS 1.4 allows remote authenticated users to execute scripts in other users' browsers via page content. The backend/pages/modify.php workflow stores attacker-supplied HTML with an onerror handler, and the preview route renders it without neutralizing the handler. An account with page-modification permission and a victim viewing the modified page are required, enabling script execution in the victim's CMS origin.

The record

CVE
CVE-2023-53891
Published
Dec 15, 2025
Updated
Dec 15, 2025
Vendor
Black Cat Development
Product
BlackCat CMS
Classifications
CWE-79, T1189
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Dec 15, 2025CVE publishedPublication date reported by the CVE source.
  2. Dec 15, 2025Record 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=1.4

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Black Cat Development · BlackCat CMSversion=1.4

Published CVSS scores

5.1VulnCheckCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N
5.4NIST NVDCVSS: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.

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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

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

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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