How severe is CVE-2021-35210?

CVE-2021-35210 has a CVSS 3.x base score of 6.1, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.

Is CVE-2021-35210 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (50th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-35210?

CVE-2021-35210 affects Contao. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-35210?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2021-35210 published?

CVE-2021-35210 was published on 2021-06-23 and last updated on 2026-06-17.

CVE-2021-35210

CVE-2021-35210 is a medium-severity vulnerability in Contao with a CVSS 3.x base score of 6.1. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-79.

Key facts

Severity: Medium (CVSS 3.x base score 6.1)
CVSS v2: 4.3
EPSS exploit prediction: 1% (50th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-79
Affected product: Contao
Published: 2021-06-23
Last modified: 2026-06-17

Description

Contao 4.5.x through 4.9.x before 4.9.16, and 4.10.x through 4.11.x before 4.11.5, allows XSS. It is possible to inject code into the tl_log table that will be executed in the browser when the system log is called in the back end.

Frequently asked questions

What is CVE-2021-35210?: Contao 4.5.x through 4.9.x before 4.9.16, and 4.10.x through 4.11.x before 4.11.5, allows XSS. It is possible to inject code into the tl_log table that will be executed in the browser when the system log is called in the back end.
How severe is CVE-2021-35210?: CVE-2021-35210 has a CVSS 3.x base score of 6.1, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.
Is CVE-2021-35210 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (50th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-35210?: CVE-2021-35210 affects Contao. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-35210?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-35210 published?: CVE-2021-35210 was published on 2021-06-23 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:contao:contao:*:*:*:*:*:*:*:*

More vulnerabilities in Contao

CVE-2022-26265 — Critical (CVSS 9.8): Contao Managed Edition v1.5.0 was discovered to contain a remote command execution (RCE) vulnerability via the…
CVE-2019-11512 — Critical (CVSS 9.8): Contao 4.x allows SQL Injection. Fixed in Contao 4.4.39 and Contao 4.7.5.
CVE-2012-4383 — High (CVSS 8.8): contao prior to 2.11.4 has a sql injection vulnerability
CVE-2019-19745 — High (CVSS 8.8): Contao 4.0 through 4.8.5 allows PHP local file inclusion. A back end user with access to the form generator can upload…
CVE-2024-45398 — High (CVSS 8.3): Contao is an Open Source CMS. In affected versions a back end user with access to the file manager can upload malicious…
CVE-2024-28235 — High (CVSS 8.3): Contao is an open source content management system. Starting in version 4.9.0 and prior to versions 4.13.40 and 5.3.4,…

All CVEs affecting Contao →

Other CWE-79 (Cross-site Scripting (XSS)) vulnerabilities

CVE-2025-49410 — Critical (CVSS 10.0): Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in Imran Emu TC…
CVE-2024-47875 — Critical (CVSS 10.0): DOMPurify is a DOM-only, super-fast, uber-tolerant XSS sanitizer for HTML, MathML and SVG. DOMpurify was vulnerable to…
CVE-2024-6886 — Critical (CVSS 10.0): Improper Neutralization of Input During Web Page Generation (XSS or 'Cross-site Scripting') vulnerability in Gitea…
CVE-2023-45144 — Critical (CVSS 10.0): com.xwiki.identity-oauth:identity-oauth-ui is a package to aid in building identity and service providers based on…
CVE-2023-45138 — Critical (CVSS 10.0): Change Request is an pplication allowing users to request changes on a wiki without publishing the changes directly.…
CVE-2022-4361 — Critical (CVSS 10.0): Keycloak, an open-source identity and access management solution, has a cross-site scripting (XSS) vulnerability in the…

Browse all CWE-79 (Cross-site Scripting (XSS)) vulnerabilities →