CVE-2021-35955
CVE-2021-35955 is a medium-severity vulnerability in Contao with a CVSS 3.x base score of 4.8. 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 4.8)
- CVSS v2: 3.5
- EPSS exploit prediction: 1% (42nd percentile)
- Actively exploited: Not listed in CISA KEV
- Weakness: CWE-79
- Affected product: Contao
- Published:
- Last modified:
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.
Frequently asked questions
- What is CVE-2021-35955?
- 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.
- How severe is CVE-2021-35955?
- CVE-2021-35955 has a CVSS 3.x base score of 4.8, rated medium severity. It is exploitable over network with low attack complexity, requires high privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.
- Is CVE-2021-35955 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (42nd percentile), an estimate of the probability of exploitation in the next 30 days.
- What products are affected by CVE-2021-35955?
- CVE-2021-35955 affects Contao. See the affected-products list for the exact vulnerable versions.
- How do I fix CVE-2021-35955?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
- When was CVE-2021-35955 published?
- CVE-2021-35955 was published on 2021-08-12 and last updated on 2026-06-17.
References
- https://contao.org/en/news/contao-4-9-16-and-4-11-5-are-available.html
- https://github.com/contao/contao/security/advisories/GHSA-hr3h-x6gq-rqcp
Affected products (1)
- cpe:2.3:a:contao:contao:*:*:*:*:*:*:*:*
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