Cross site scripting via input unit widget

CVE-2023-36806 → View on GitHub ↗ View on CVE.org ↗ View on NVD ↗

Description

Impact

Authenticated users can inject malicious code in widgets with units, which is then executed both in the element preview (back end) and on the website (front end).

Patches

Update to Contao 4.9.42, 4.13.28 or 5.1.10.

Workarounds

Disable login for all untrusted back end users.

References

https://contao.org/en/security-advisories/cross-site-scripting-in-widgets-with-units

For more information

If you have any questions or comments about this advisory, open an issue in contao/contao.

Credits

Thanks to Christian Pöschl and Fabian Brenner from usd AG for reporting this vulnerability.

Basic information

Type
reviewed
Severity
medium
Advisory on GitHub
Open advisory ↗
Repository advisory
Open repository advisory ↗
Source code
Browse source ↗
Published (advisory)
2023-07-25 17:19:10 UTC
Updated
2025-04-17 12:44:38 UTC
GitHub reviewed
2023-07-25 17:19:10 UTC
NVD published
2023-07-25

EPSS Score

Score Percentile
0.19% 41.49%

CVSS Scores

Base score Version Severity Vector
6.6 3.1 —
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:L/I:L/A:L Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:H)
They need powerful rights—admin, root, or similar—before this pays off.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:L)
Some sensitive info could get out, but not a total data dump.
Integrity (I:L)
Attackers could change some data, but it’s limited—not everything goes.
Availability (A:L)
Might cause slowdowns, glitches, or partial disruption—not a full brick.

Identifiers

Type Value
GHSA GHSA-4gpr-p634-922x ↗
CVE CVE-2023-36806 ↗

CWEs

CWE id Name
CWE-79 Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Affected packages (3)

Vulnerable version ranges and first patched releases as published by GitHub.

Ecosystem Package Vulnerable range First patched Vulnerable functions
composer contao/core-bundle >= 4.0.0, < 4.9.42 4.9.42 —
composer contao/core-bundle >= 4.10.0, < 4.13.28 4.13.28 —
composer contao/core-bundle >= 5.0.0, < 5.1.10 5.1.10 —

References

cvelogic Threat Intelligence