CVE-2023-36806Public exploitNetwork attack vector

Stored XSS via unchecked headline unit tag

Published Jul 25, 2023 · Updated Feb 13, 2025

Stored XSS in affected Contao releases allows remote authenticated users to execute scripts through a crafted headline unit. The InputUnit, TimePeriod, and TrblField validators accept a supplied unit such as script without checking it against configured options, so rendering uses it as an HTML tag. A backend account permitted to modify headline or other input-unit fields is required, and the payload runs in backend previews and site pages viewed by others.

CVSS severity4.6
Medium
EPSS probability0.64%
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 affected Contao releases allows remote authenticated users to execute scripts through a crafted headline unit. The InputUnit, TimePeriod, and TrblField validators accept a supplied unit such as script without checking it against configured options, so rendering uses it as an HTML tag. A backend account permitted to modify headline or other input-unit fields is required, and the payload runs in backend previews and site pages viewed by others.

The record

CVE
CVE-2023-36806
Published
Jul 25, 2023
Updated
Feb 13, 2025
Vendor
Contao
Product
Contao
Classifications
CWE-79, T1059.007
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jul 25, 2023CVE publishedPublication date reported by the CVE source.
  2. Feb 13, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

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

  1. Affected versionversion=0 <=4.0.0
  2. Affected versionversion=0 <=4.10.0
  3. Affected versionversion=0 <4.13.28
  4. Affected versionversion=0 <4.9.42
  5. Affected versionversion=0 <=5.0.0
  6. Affected versionversion=0 <5.1.10
  7. Affected versionversion=>= 4.0.0, < 4.9.42
  8. Affected versionversion=>= 4.10.0, < 4.13.28
  9. Affected versionversion=>= 5.0.0, < 5.1.10

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Contao · Contaoversion=0 <=4.0.0; version=0 <=4.10.0; version=0 <4.13.28; version=0 <4.9.42; version=0 <=5.0.0; version=0 <5.1.10; version=>= 4.0.0, < 4.9.42; version=>= 4.10.0, < 4.13.28; version=>= 5.0.0, < 5.1.10

Published CVSS scores

5.4NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
4.6GitHubCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/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')
T1059.007JavaScript/JScript

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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