Contao: Unencoded insert tags in the frontend

Description

Impact

It is possible to inject insert tags via the form generator if the submitted form data is output on the page in a specific way.

Patches

Update to Contao 4.13.40 or 5.3.4.

Workarounds

Do not output the submitted form data on the website.

References

https://contao.org/en/security-advisories/insert-tag-injection-via-the-form-generator

For more information

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

Basic information

Type
reviewed
Severity
low
Advisory on GitHub
Open advisory ↗
Repository advisory
Open repository advisory ↗
Source code
Browse source ↗
Published (advisory)
2024-04-09 18:52:51 UTC
Updated
2024-04-09 18:52:57 UTC
GitHub reviewed
2024-04-09 18:52:51 UTC
NVD published
2024-04-09

EPSS Score

Score Percentile
0.96% 76.52%

CVSS Scores

Base score Version Severity Vector
3.1 3.1
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:N/A:N 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:H)
Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:L)
Some sensitive info could get out, but not a total data dump.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:N)
Service keeps running; no real outage angle.

Identifiers

CWEs

CWE id Name
CWE-74 Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')

Affected packages (2)

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, < 4.13.40 4.13.40
composer contao/core-bundle >= 5.0.0-RC1, < 5.3.4 5.3.4

References

cvelogic Threat Intelligence