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.

Published: 2021-07-27 Last update: 2026-06-16 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2021-20399 is rated Moderate Risk (64/100): CVSS Critical severity, with medium exploitation likelihood (EPSS 1.79%). EPSS rose +1.24% over the last day, indicating growing attacker interest. 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-2021-20399

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 0.55% 1.79% +1.24%
2 2025-11-21 0.34% 0.55% +0.21%
3 2025-11-18 — 0.34% —

Full EPSS history (13 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-20399

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
9.1 3.1 CRITICAL
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H 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:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 3.9 5.2 [email protected]
7.1 3.0 HIGH
CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:L 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:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:L)
Might cause slowdowns, glitches, or partial disruption—not a full brick.
 2.8 4.2 [email protected]
6.4 2.0 MEDIUM
AV:N/AC:L/Au:N/C:P/I:N/A:P Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:P)
Partial confidentiality impact.
Integrity impact (I:N)
No integrity impact.
Availability impact (A:P)
Partial availability impact.
 10.0 4.9 [email protected]

Weakness enumeration for CVE-2021-20399

Affected software / configurations for CVE-2021-20399

Vendor Product Version Raw CPE
ibm qradar_security_information_and_event_manager >= 7.3.0, < 7.3.3 cpe:2.3:a:ibm:qradar_security_information_and_event_manager:*:*:*:*:*:*:*:*
ibm qradar_security_information_and_event_manager >= 7.4.0, < 7.4.3 cpe:2.3:a:ibm:qradar_security_information_and_event_manager:*:*:*:*:*:*:*:*
ibm qradar_security_information_and_event_manager 7.3.3 cpe:2.3:a:ibm:qradar_security_information_and_event_manager:7.3.3:-:*:*:*:*:*:*
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:*:*:*:*:*:*
ibm qradar_security_information_and_event_manager 7.3.3 cpe:2.3:a:ibm:qradar_security_information_and_event_manager:7.3.3:p2:*:*:*:*:*:*
ibm qradar_security_information_and_event_manager 7.3.3 cpe:2.3:a:ibm:qradar_security_information_and_event_manager:7.3.3:p3:*:*:*:*:*:*
ibm qradar_security_information_and_event_manager 7.3.3 cpe:2.3:a:ibm:qradar_security_information_and_event_manager:7.3.3:p4:*:*:*:*:*:*
ibm qradar_security_information_and_event_manager 7.3.3 cpe:2.3:a:ibm:qradar_security_information_and_event_manager:7.3.3:p5:*:*:*:*:*:*
ibm qradar_security_information_and_event_manager 7.3.3 cpe:2.3:a:ibm:qradar_security_information_and_event_manager:7.3.3:p6:*:*:*:*:*:*
ibm qradar_security_information_and_event_manager 7.3.3 cpe:2.3:a:ibm:qradar_security_information_and_event_manager:7.3.3:p7:*:*:*:*:*:*
ibm qradar_security_information_and_event_manager 7.3.3 cpe:2.3:a:ibm:qradar_security_information_and_event_manager:7.3.3:p8:*:*:*:*:*:*
ibm qradar_security_information_and_event_manager 7.4.3 cpe:2.3:a:ibm:qradar_security_information_and_event_manager:7.4.3:-:*:*:*:*:*:*
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:*:*:*:*:*:*
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_2:*:*:*:*:*:*
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_3:*:*:*:*:*:*

References for CVE-2021-20399

cvelogic Threat Intelligence