How severe is CVE-2021-20399?

CVE-2021-20399 has a CVSS 3.x base score of 9.1, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability high.

Is CVE-2021-20399 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (76th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-20399?

CVE-2021-20399 primarily affects Ibm Qradar Security Information And Event Manager. In total, 14 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-20399?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

When was CVE-2021-20399 published?

CVE-2021-20399 was published on 2021-07-27 and last updated on 2026-06-17.

CVE-2021-20399

CVE-2021-20399 is a critical-severity vulnerability in Ibm Qradar Security Information And Event Manager with a CVSS 3.x base score of 9.1. 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-611.

Key facts

Severity: Critical (CVSS 3.x base score 9.1)
CVSS v2: 6.4
EPSS exploit prediction: 2% (76th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-611
Affected product: Ibm Qradar Security Information And Event Manager
Published: 2021-07-27
Last modified: 2026-06-17

Description

IBM Qradar SIEM 7.3.0 to 7.3.3 Patch 8 and 7.4.0 to 7.4.3 GA is vulnerable to an XML External Entity Injection (XXE) attack when processing XML data. A remote attacker could exploit this vulnerability to expose sensitive information or consume memory resources. IBM X-Force ID: 196073.

Frequently asked questions

What is CVE-2021-20399?: IBM Qradar SIEM 7.3.0 to 7.3.3 Patch 8 and 7.4.0 to 7.4.3 GA is vulnerable to an XML External Entity Injection (XXE) attack when processing XML data. A remote attacker could exploit this vulnerability to expose sensitive information or consume memory resources. IBM X-Force ID: 196073.
How severe is CVE-2021-20399?: CVE-2021-20399 has a CVSS 3.x base score of 9.1, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability high.
Is CVE-2021-20399 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (76th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-20399?: CVE-2021-20399 primarily affects Ibm Qradar Security Information And Event Manager. In total, 14 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-20399?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2021-20399 published?: CVE-2021-20399 was published on 2021-07-27 and last updated on 2026-06-17.

References

Affected products (14)

cpe:2.3:a:ibm:qradar_security_information_and_event_manager:*:*:*:*:*:*:*:*
cpe:2.3:a:ibm:qradar_security_information_and_event_manager:7.3.3:-:*:*:*:*:*:*
cpe:2.3:a:ibm:qradar_security_information_and_event_manager:7.3.3:p1:*:*:*:*:*:*
cpe:2.3:a:ibm:qradar_security_information_and_event_manager:7.3.3:p2:*:*:*:*:*:*
cpe:2.3:a:ibm:qradar_security_information_and_event_manager:7.3.3:p3:*:*:*:*:*:*
cpe:2.3:a:ibm:qradar_security_information_and_event_manager:7.3.3:p4:*:*:*:*:*:*
cpe:2.3:a:ibm:qradar_security_information_and_event_manager:7.3.3:p5:*:*:*:*:*:*
cpe:2.3:a:ibm:qradar_security_information_and_event_manager:7.3.3:p6:*:*:*:*:*:*
cpe:2.3:a:ibm:qradar_security_information_and_event_manager:7.3.3:p7:*:*:*:*:*:*
cpe:2.3:a:ibm:qradar_security_information_and_event_manager:7.3.3:p8:*:*:*:*:*:*
cpe:2.3:a:ibm:qradar_security_information_and_event_manager:7.4.3:-:*:*:*:*:*:*
cpe:2.3:a:ibm:qradar_security_information_and_event_manager:7.4.3:fix_pack_1:*:*:*:*:*:*
cpe:2.3:a:ibm:qradar_security_information_and_event_manager:7.4.3:fix_pack_2:*:*:*:*:*:*
cpe:2.3:a:ibm:qradar_security_information_and_event_manager:7.4.3:fix_pack_3:*:*:*:*:*:*

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Other CWE-611 (Improper Restriction of XML External Entity Reference (XXE)) vulnerabilities

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