CVE-2021-35955: Contao >=4.0.0 allows backend XSS via HTML attributes to an HTML field

Medium severity · published Aug 12, 2021

CVE-2021-35955

Contao >=4.0.0 allows backend XSS via HTML attributes to an HTML field

4.8

CVSS

0.6%

EPSS

On KEV

Description

Contao >=4.0.0 allows backend XSS via HTML attributes to an HTML field. Fixed in 4.4.56, 4.9.18, 4.11.7.

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N

Attack vector

Network

Complexity

Low

Privileges

High

User interaction

Required

Confidentiality

Low

Integrity

Low

Availability

None

Scope

Changed

Exploitation

Is it being used?

Exploit prediction (EPSS)0.6% · higher than 46% of CVEs

Exploited in the wildNo evidence yet

CISA KEVNot listed

Ransomware campaign useNot known

Affected products

Which versions

Contao · Contao

4.0.0 before 4.4.56; 4.5.0 before 4.9.18; 4.10.0 before 4.11.7 · source: NVD

Affected product

Contao

All Contao CVEs

References

NVD

https://nvd.nist.gov/vuln/detail/CVE-2021-35955

CVE.org

https://www.cve.org/CVERecord?id=CVE-2021-35955

Vendor Advisory

https://contao.org/en/news/contao-4-9-16-and-4-11-5-are-available.html

Third Party Advisory

https://github.com/contao/contao/security/advisories/GHSA-hr3h-x6gq-rqcp