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.

Published: 2021-03-10 Last update: 2024-11-21 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2021-21491 is rated Moderate Risk (41.4/100): CVSS Medium severity, with low exploitation likelihood (EPSS 0.67%). Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2021-21491

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 0.08% 0.67% +0.59%
2 2023-03-07 0.89% 0.08% -0.81%
3 2022-04-01 — 0.89% —

Full EPSS history (6 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-21491

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
6.1 3.1 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:L)
Some sensitive info could get out, but not a total data dump.
Integrity (I:L)
Attackers could change some data, but it’s limited—not everything goes.
Availability (A:N)
Service keeps running; no real outage angle.
 2.8 2.7 [email protected]
4.7 3.0 MEDIUM
CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:N/I:L/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:L)
Attackers could change some data, but it’s limited—not everything goes.
Availability (A:N)
Service keeps running; no real outage angle.
 2.8 1.4 [email protected]
5.8 2.0 MEDIUM
AV:N/AC:M/Au:N/C:P/I:P/A:N Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:M)
Exploitation needs some favorable conditions, but not exceptional ones.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:P)
Partial confidentiality impact.
Integrity impact (I:P)
Partial integrity impact.
Availability impact (A:N)
No availability impact.
 8.6 4.9 [email protected]

Weakness enumeration for CVE-2021-21491

Affected software / configurations for CVE-2021-21491

Vendor Product Version Raw CPE
sap netweaver_application_server_java 7.00 cpe:2.3:a:sap:netweaver_application_server_java:7.00:*:*:*:*:*:*:*
sap netweaver_application_server_java 7.10 cpe:2.3:a:sap:netweaver_application_server_java:7.10:*:*:*:*:*:*:*
sap netweaver_application_server_java 7.11 cpe:2.3:a:sap:netweaver_application_server_java:7.11:*:*:*:*:*:*:*
sap netweaver_application_server_java 7.20 cpe:2.3:a:sap:netweaver_application_server_java:7.20:*:*:*:*:*:*:*
sap netweaver_application_server_java 7.30 cpe:2.3:a:sap:netweaver_application_server_java:7.30:*:*:*:*:*:*:*
sap netweaver_application_server_java 7.31 cpe:2.3:a:sap:netweaver_application_server_java:7.31:*:*:*:*:*:*:*
sap netweaver_application_server_java 7.40 cpe:2.3:a:sap:netweaver_application_server_java:7.40:*:*:*:*:*:*:*
sap netweaver_application_server_java 7.50 cpe:2.3:a:sap:netweaver_application_server_java:7.50:*:*:*:*:*:*:*

References for CVE-2021-21491

cvelogic Threat Intelligence