How severe is CVE-2021-21491?

CVE-2021-21491 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-2021-21491 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (47th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-21491?

CVE-2021-21491 primarily affects Sap Netweaver Application Server Java. In total, 8 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-21491?

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

When was CVE-2021-21491 published?

CVE-2021-21491 was published on 2021-03-10 and last updated on 2026-06-17.

CVE-2021-21491

CVE-2021-21491 is a medium-severity vulnerability in Sap Netweaver Application Server Java 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-601.

Key facts

Severity: Medium (CVSS 3.x base score 6.1)
CVSS v2: 5.8
EPSS exploit prediction: 1% (47th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-601
Affected product: Sap Netweaver Application Server Java
Published: 2021-03-10
Last modified: 2026-06-17

Description

SAP Netweaver Application Server Java (Applications based on WebDynpro Java) versions 7.00, 7.10, 7.11, 7.20, 7.30, 7.31, 7.40, 7.50, allow an attacker to redirect users to a malicious site due to Reverse Tabnabbing vulnerabilities.

Frequently asked questions

What is CVE-2021-21491?: SAP Netweaver Application Server Java (Applications based on WebDynpro Java) versions 7.00, 7.10, 7.11, 7.20, 7.30, 7.31, 7.40, 7.50, allow an attacker to redirect users to a malicious site due to Reverse Tabnabbing vulnerabilities.
How severe is CVE-2021-21491?: CVE-2021-21491 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-2021-21491 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (47th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-21491?: CVE-2021-21491 primarily affects Sap Netweaver Application Server Java. In total, 8 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-21491?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-21491 published?: CVE-2021-21491 was published on 2021-03-10 and last updated on 2026-06-17.

References

Affected products (8)

cpe:2.3:a:sap:netweaver_application_server_java:7.00:*:*:*:*:*:*:*
cpe:2.3:a:sap:netweaver_application_server_java:7.10:*:*:*:*:*:*:*
cpe:2.3:a:sap:netweaver_application_server_java:7.11:*:*:*:*:*:*:*
cpe:2.3:a:sap:netweaver_application_server_java:7.20:*:*:*:*:*:*:*
cpe:2.3:a:sap:netweaver_application_server_java:7.30:*:*:*:*:*:*:*
cpe:2.3:a:sap:netweaver_application_server_java:7.31:*:*:*:*:*:*:*
cpe:2.3:a:sap:netweaver_application_server_java:7.40:*:*:*:*:*:*:*
cpe:2.3:a:sap:netweaver_application_server_java:7.50:*:*:*:*:*:*:*

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