Evidence dossier

CVE-2021-22991

CVE-2021-22991

72.6–95.1Priority evidence range

As known Jul 19, 2026, 5:00 AM UTCgen-56ccdaf9

Normalized restatement

On BIG-IP versions 16.0.x before 16.0.1.1, 15.1.x before 15.1.2.1, 14.1.x before 14.1.4, 13.1.x before 13.1.3.6, and 12.1.x before 12.1.5.3, undisclosed requests to a virtual server may be incorrectly handled by the Traffic Management Microkernel (TMM) URI normalization, which may trigger a buffer overflow, resulting in a DoS attack. In certain situations, it may theoretically allow bypass of URL based access control or remote code execution (RCE). Note: Software versions which have reached End of Software Development (EoSD) are not evaluated.

State: PUBLISHED
Published: Mar 31, 2021
Updated: Oct 21, 2025
Evidence coverage: 72%

CISA KEVCatalog member

Apply updates per vendor instructions.

FIRST EPSS61.06%

2026-07-18 · v2026.06.15 · percentile 99.1%

Source stateConflict visible

Distinct CVSS assessments remain side by side; none are averaged.

Source comparison

Who said what

CISA-ADPindependent enrichment

container

CISA ADP Vulnrichment

Jul 19, 2026Original evidence ↗

CVEderivative copy

container

CVE Program Container

Jul 19, 2026Original evidence ↗

f5original assertion

container

On BIG-IP versions 16.0.x before 16.0.1.1, 15.1.x before 15.1.2.1, 14.1.x before 14.1.4, 13.1.x before 13.1.3.6, and 12.1.x before 12.1.5.3, undisclosed requests to a virtual server may be incorrectly handled by the Traffic Management Microkernel (TMM) URI normalization, which may trigger a buffer overflow, resulting in a DoS attack. In certain situations, it may theoretically allow bypass of URL based access control or remote code execution (RCE). Note: Software versions which have reached End of Software Development (EoSD) are not evaluated.

Jul 19, 2026Original evidence ↗

CISA KEVoriginal assertion

observed_exploitation

F5 BIG-IP Traffic Management Microkernel Buffer Overflow

Jul 19, 2026Original evidence ↗

FIRST EPSSoriginal assertion

model_probability

Probability 0.610640000000; percentile 0.990590000000

Jul 19, 2026Original evidence ↗

Applicability

Cited product scope

Trace impact →

n/aBIG-IP

[{"status": "affected", "version": "16.0.x before 16.0.1.1, 15.1.x before 15.1.2.1, 14.1.x before 14.1.4, 13.1.x before 13.1.3.6, 12.1.x before 12.1.5.3"}]

unknown

Unknown vendorUnknown product

cpe:2.3:a:f5:big-ip_access_policy_manager:*:*:*:*:*:*:*:*; start including 12.1.0; end excluding 12.1.5.3supported

Unknown vendorUnknown product

cpe:2.3:a:f5:big-ip_access_policy_manager:*:*:*:*:*:*:*:*; start including 13.1.0; end excluding 13.1.3.6supported

Unknown vendorUnknown product

cpe:2.3:a:f5:big-ip_access_policy_manager:*:*:*:*:*:*:*:*; start including 14.1.0; end excluding 14.1.4supported

Unknown vendorUnknown product

cpe:2.3:a:f5:big-ip_access_policy_manager:*:*:*:*:*:*:*:*; start including 15.1.0; end excluding 15.1.2.1supported

Unknown vendorUnknown product

cpe:2.3:a:f5:big-ip_access_policy_manager:*:*:*:*:*:*:*:*; start including 16.0.0; end excluding 16.0.1.1supported

Unknown vendorUnknown product

cpe:2.3:a:f5:big-ip_advanced_firewall_manager:*:*:*:*:*:*:*:*; start including 12.1.0; end excluding 12.1.5.3supported

Unknown vendorUnknown product

cpe:2.3:a:f5:big-ip_advanced_firewall_manager:*:*:*:*:*:*:*:*; start including 13.1.0; end excluding 13.1.3.6supported

Unknown vendorUnknown product

cpe:2.3:a:f5:big-ip_advanced_firewall_manager:*:*:*:*:*:*:*:*; start including 14.1.0; end excluding 14.1.4supported

Unknown vendorUnknown product

cpe:2.3:a:f5:big-ip_advanced_firewall_manager:*:*:*:*:*:*:*:*; start including 15.1.0; end excluding 15.1.2.1supported

Unknown vendorUnknown product

cpe:2.3:a:f5:big-ip_advanced_firewall_manager:*:*:*:*:*:*:*:*; start including 16.0.0; end excluding 16.0.1.1supported

Unknown vendorUnknown product

cpe:2.3:a:f5:big-ip_advanced_web_application_firewall:*:*:*:*:*:*:*:*; start including 12.1.0; end excluding 12.1.5.3supported

Unknown vendorUnknown product

cpe:2.3:a:f5:big-ip_advanced_web_application_firewall:*:*:*:*:*:*:*:*; start including 13.1.0; end excluding 13.1.3.6supported

Unknown vendorUnknown product

cpe:2.3:a:f5:big-ip_advanced_web_application_firewall:*:*:*:*:*:*:*:*; start including 14.1.0; end excluding 14.1.4supported

Unknown vendorUnknown product

cpe:2.3:a:f5:big-ip_advanced_web_application_firewall:*:*:*:*:*:*:*:*; start including 15.1.0; end excluding 15.1.2.1supported

Unknown vendorUnknown product

cpe:2.3:a:f5:big-ip_advanced_web_application_firewall:*:*:*:*:*:*:*:*; start including 16.0.0; end excluding 16.0.1.1supported

Unknown vendorUnknown product

cpe:2.3:a:f5:big-ip_analytics:*:*:*:*:*:*:*:*; start including 12.1.0; end excluding 12.1.5.3supported

Unknown vendorUnknown product

cpe:2.3:a:f5:big-ip_analytics:*:*:*:*:*:*:*:*; start including 13.1.0; end excluding 13.1.3.6supported

Unknown vendorUnknown product

cpe:2.3:a:f5:big-ip_analytics:*:*:*:*:*:*:*:*; start including 14.1.0; end excluding 14.1.4supported

Unknown vendorUnknown product

cpe:2.3:a:f5:big-ip_analytics:*:*:*:*:*:*:*:*; start including 15.1.0; end excluding 15.1.2.1supported

Unknown vendorUnknown product

cpe:2.3:a:f5:big-ip_analytics:*:*:*:*:*:*:*:*; start including 16.0.0; end excluding 16.0.1.1supported

Unknown vendorUnknown product

cpe:2.3:a:f5:big-ip_application_acceleration_manager:*:*:*:*:*:*:*:*; start including 12.1.0; end excluding 12.1.5.3supported

Unknown vendorUnknown product

cpe:2.3:a:f5:big-ip_application_acceleration_manager:*:*:*:*:*:*:*:*; start including 13.1.0; end excluding 13.1.3.6supported

Unknown vendorUnknown product

cpe:2.3:a:f5:big-ip_application_acceleration_manager:*:*:*:*:*:*:*:*; start including 14.1.0; end excluding 14.1.4supported

Unknown vendorUnknown product

cpe:2.3:a:f5:big-ip_application_acceleration_manager:*:*:*:*:*:*:*:*; start including 15.1.0; end excluding 15.1.2.1supported

Unknown vendorUnknown product

cpe:2.3:a:f5:big-ip_application_acceleration_manager:*:*:*:*:*:*:*:*; start including 16.0.0; end excluding 16.0.1.1supported

Unknown vendorUnknown product

cpe:2.3:a:f5:big-ip_application_security_manager:*:*:*:*:*:*:*:*; start including 12.1.0; end excluding 12.1.5.3supported

Unknown vendorUnknown product

cpe:2.3:a:f5:big-ip_application_security_manager:*:*:*:*:*:*:*:*; start including 13.1.0; end excluding 13.1.3.6supported

Unknown vendorUnknown product

cpe:2.3:a:f5:big-ip_application_security_manager:*:*:*:*:*:*:*:*; start including 14.1.0; end excluding 14.1.4supported

Unknown vendorUnknown product

cpe:2.3:a:f5:big-ip_application_security_manager:*:*:*:*:*:*:*:*; start including 15.1.0; end excluding 15.1.2.1supported

Unknown vendorUnknown product

cpe:2.3:a:f5:big-ip_application_security_manager:*:*:*:*:*:*:*:*; start including 16.0.0; end excluding 16.0.1.1supported

Unknown vendorUnknown product

cpe:2.3:a:f5:big-ip_ddos_hybrid_defender:*:*:*:*:*:*:*:*; start including 12.1.0; end excluding 12.1.5.3supported

Unknown vendorUnknown product

cpe:2.3:a:f5:big-ip_ddos_hybrid_defender:*:*:*:*:*:*:*:*; start including 13.1.0; end excluding 13.1.3.6supported

Unknown vendorUnknown product

cpe:2.3:a:f5:big-ip_ddos_hybrid_defender:*:*:*:*:*:*:*:*; start including 14.1.0; end excluding 14.1.4supported

Unknown vendorUnknown product

cpe:2.3:a:f5:big-ip_ddos_hybrid_defender:*:*:*:*:*:*:*:*; start including 15.1.0; end excluding 15.1.2.1supported

Unknown vendorUnknown product

cpe:2.3:a:f5:big-ip_ddos_hybrid_defender:*:*:*:*:*:*:*:*; start including 16.0.0; end excluding 16.0.1.1supported

Unknown vendorUnknown product

cpe:2.3:a:f5:big-ip_domain_name_system:*:*:*:*:*:*:*:*; start including 12.1.0; end excluding 12.1.5.3supported

Unknown vendorUnknown product

cpe:2.3:a:f5:big-ip_domain_name_system:*:*:*:*:*:*:*:*; start including 13.1.0; end excluding 13.1.3.6supported

Unknown vendorUnknown product

cpe:2.3:a:f5:big-ip_domain_name_system:*:*:*:*:*:*:*:*; start including 14.1.0; end excluding 14.1.4supported

Unknown vendorUnknown product

cpe:2.3:a:f5:big-ip_domain_name_system:*:*:*:*:*:*:*:*; start including 15.1.0; end excluding 15.1.2.1supported

Unknown vendorUnknown product

cpe:2.3:a:f5:big-ip_domain_name_system:*:*:*:*:*:*:*:*; start including 16.0.0; end excluding 16.0.1.1supported

Unknown vendorUnknown product

cpe:2.3:a:f5:big-ip_fraud_protection_service:*:*:*:*:*:*:*:*; start including 12.1.0; end excluding 12.1.5.3supported

Unknown vendorUnknown product

cpe:2.3:a:f5:big-ip_fraud_protection_service:*:*:*:*:*:*:*:*; start including 13.1.0; end excluding 13.1.3.6supported

Unknown vendorUnknown product

cpe:2.3:a:f5:big-ip_fraud_protection_service:*:*:*:*:*:*:*:*; start including 14.1.0; end excluding 14.1.4supported

Unknown vendorUnknown product

cpe:2.3:a:f5:big-ip_fraud_protection_service:*:*:*:*:*:*:*:*; start including 15.1.0; end excluding 15.1.2.1supported

Unknown vendorUnknown product

cpe:2.3:a:f5:big-ip_fraud_protection_service:*:*:*:*:*:*:*:*; start including 16.0.0; end excluding 16.0.1.1supported

Unknown vendorUnknown product

cpe:2.3:a:f5:big-ip_global_traffic_manager:*:*:*:*:*:*:*:*; start including 12.1.0; end excluding 12.1.5.3supported

Unknown vendorUnknown product

cpe:2.3:a:f5:big-ip_global_traffic_manager:*:*:*:*:*:*:*:*; start including 13.1.0; end excluding 13.1.3.6supported

Unknown vendorUnknown product

cpe:2.3:a:f5:big-ip_global_traffic_manager:*:*:*:*:*:*:*:*; start including 14.1.0; end excluding 14.1.4supported

Unknown vendorUnknown product

cpe:2.3:a:f5:big-ip_global_traffic_manager:*:*:*:*:*:*:*:*; start including 15.1.0; end excluding 15.1.2.1supported

Unknown vendorUnknown product

cpe:2.3:a:f5:big-ip_global_traffic_manager:*:*:*:*:*:*:*:*; start including 16.0.0; end excluding 16.0.1.1supported

Unknown vendorUnknown product

cpe:2.3:a:f5:big-ip_link_controller:*:*:*:*:*:*:*:*; start including 12.1.0; end excluding 12.1.5.3supported

Unknown vendorUnknown product

cpe:2.3:a:f5:big-ip_link_controller:*:*:*:*:*:*:*:*; start including 13.1.0; end excluding 13.1.3.6supported

Unknown vendorUnknown product

cpe:2.3:a:f5:big-ip_link_controller:*:*:*:*:*:*:*:*; start including 14.1.0; end excluding 14.1.4supported

Unknown vendorUnknown product

cpe:2.3:a:f5:big-ip_link_controller:*:*:*:*:*:*:*:*; start including 15.1.0; end excluding 15.1.2.1supported

Unknown vendorUnknown product

cpe:2.3:a:f5:big-ip_link_controller:*:*:*:*:*:*:*:*; start including 16.0.0; end excluding 16.0.1.1supported

Unknown vendorUnknown product

cpe:2.3:a:f5:big-ip_local_traffic_manager:*:*:*:*:*:*:*:*; start including 12.1.0; end excluding 12.1.5.3supported

Unknown vendorUnknown product

cpe:2.3:a:f5:big-ip_local_traffic_manager:*:*:*:*:*:*:*:*; start including 13.1.0; end excluding 13.1.3.6supported

Unknown vendorUnknown product

cpe:2.3:a:f5:big-ip_local_traffic_manager:*:*:*:*:*:*:*:*; start including 14.1.0; end excluding 14.1.4supported

Unknown vendorUnknown product

cpe:2.3:a:f5:big-ip_local_traffic_manager:*:*:*:*:*:*:*:*; start including 15.1.0; end excluding 15.1.2.1supported

Unknown vendorUnknown product

cpe:2.3:a:f5:big-ip_local_traffic_manager:*:*:*:*:*:*:*:*; start including 16.0.0; end excluding 16.0.1.1supported

Unknown vendorUnknown product

cpe:2.3:a:f5:big-ip_policy_enforcement_manager:*:*:*:*:*:*:*:*; start including 12.1.0; end excluding 12.1.5.3supported

Unknown vendorUnknown product

cpe:2.3:a:f5:big-ip_policy_enforcement_manager:*:*:*:*:*:*:*:*; start including 13.1.0; end excluding 13.1.3.6supported

Unknown vendorUnknown product

cpe:2.3:a:f5:big-ip_policy_enforcement_manager:*:*:*:*:*:*:*:*; start including 14.1.0; end excluding 14.1.4supported

Unknown vendorUnknown product

cpe:2.3:a:f5:big-ip_policy_enforcement_manager:*:*:*:*:*:*:*:*; start including 15.1.0; end excluding 15.1.2.1supported

Unknown vendorUnknown product

cpe:2.3:a:f5:big-ip_policy_enforcement_manager:*:*:*:*:*:*:*:*; start including 16.0.0; end excluding 16.0.1.1supported

Unknown vendorUnknown product

cpe:2.3:a:f5:ssl_orchestrator:*:*:*:*:*:*:*:*; start including 12.1.0; end excluding 12.1.5.3supported

Unknown vendorUnknown product

cpe:2.3:a:f5:ssl_orchestrator:*:*:*:*:*:*:*:*; start including 13.1.0; end excluding 13.1.3.6supported

Unknown vendorUnknown product

cpe:2.3:a:f5:ssl_orchestrator:*:*:*:*:*:*:*:*; start including 14.1.0; end excluding 14.1.4supported

Unknown vendorUnknown product

cpe:2.3:a:f5:ssl_orchestrator:*:*:*:*:*:*:*:*; start including 15.1.0; end excluding 15.1.2.1supported

Unknown vendorUnknown product

cpe:2.3:a:f5:ssl_orchestrator:*:*:*:*:*:*:*:*; start including 16.0.0; end excluding 16.0.1.1supported

Assessments

CVSS by origin

9.8

nvd@nist.govCVSS 3.1 · role PrimaryCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

6.8

nvd@nist.govCVSS 2.0 · role PrimaryAV:N/AC:M/Au:N/C:P/I:P/A:P

9.8

134c704f-9b21-4f2e-91b3-4a467353bcc0CVSS 3.1 · role SecondaryCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

9.8

CISA-ADPCVSS 3.1 · role unknownCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Limitations and unknowns

KEV membership is authoritative for the catalog, not proof of exposure in any environment.
EPSS is a dated model probability and not an individual-environment prediction.
Affected or fixed status applies only to the exact cited product and version scope; unresolved scope remains unknown.
NVD-carried upstream facts remain derivative and are not independent corroboration.
Only NVD metrics validated under the generation-bound calculator are Public Priority eligible; direct CVE record metrics remain display-only.
NVD CVSS source eligibility is closed: NVD-authored, exact record-source, or registered same-CVE container origin; unmapped sources remain display-only.
Factor D is unknown in Public Core because no accepted canonical mapping-obligation ledger is present.
Core replay supports the active and immediately prior generation; retrospective valid-at replay is deferred.