How severe is CVE-2021-21338?

CVE-2021-21338 has a CVSS 3.x base score of 4.7, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is none, integrity low, and availability none.

Is CVE-2021-21338 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (62nd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-21338?

CVE-2021-21338 affects Typo3. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-21338?

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

When was CVE-2021-21338 published?

CVE-2021-21338 was published on 2021-03-23 and last updated on 2026-06-17.

CVE-2021-21338

CVE-2021-21338 is a medium-severity vulnerability in Typo3 with a CVSS 3.x base score of 4.7. 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-601.

Key facts

Severity: Medium (CVSS 3.x base score 4.7)
CVSS v2: 5.8
EPSS exploit prediction: 1% (62nd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-601
Affected product: Typo3
Published: 2021-03-23
Last modified: 2026-06-17

Description

TYPO3 is an open source PHP based web content management system. In TYPO3 before versions 6.2.57, 7.6.51, 8.7.40, 9.5.25, 10.4.14, 11.1.1 it has been discovered that Login Handling is susceptible to open redirection which allows attackers redirecting to arbitrary content, and conducting phishing attacks. No authentication is required in order to exploit this vulnerability. This is fixed in versions 6.2.57, 7.6.51, 8.7.40, 9.5.25, 10.4.14, 11.1.1.

Frequently asked questions

What is CVE-2021-21338?: TYPO3 is an open source PHP based web content management system. In TYPO3 before versions 6.2.57, 7.6.51, 8.7.40, 9.5.25, 10.4.14, 11.1.1 it has been discovered that Login Handling is susceptible to open redirection which allows attackers redirecting to arbitrary content, and conducting phishing attacks. No authentication is required in order to exploit this vulnerability. This is fixed in versions 6.2.57, 7.6.51, 8.7.40, 9.5.25, 10.4.14, 11.1.1.
How severe is CVE-2021-21338?: CVE-2021-21338 has a CVSS 3.x base score of 4.7, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is none, integrity low, and availability none.
Is CVE-2021-21338 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (62nd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-21338?: CVE-2021-21338 affects Typo3. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-21338?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-21338 published?: CVE-2021-21338 was published on 2021-03-23 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:typo3:typo3:*:*:*:*:*:*:*:*

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