How severe is CVE-2019-6594?

CVE-2019-6594 has a CVSS 3.x base score of 5.9, rated medium severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2019-6594 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (59th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2019-6594?

CVE-2019-6594 primarily affects F5 Big-ip Access Policy Manager. In total, 48 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2019-6594?

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

When was CVE-2019-6594 published?

CVE-2019-6594 was published on 2019-02-26 and last updated on 2026-06-17.

CVE-2019-6594

CVE-2019-6594 is a medium-severity vulnerability in F5 Big-ip Access Policy Manager with a CVSS 3.x base score of 5.9. 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-835.

Key facts

Severity: Medium (CVSS 3.x base score 5.9)
CVSS v2: 4.3
EPSS exploit prediction: 1% (59th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-835
Affected product: F5 Big-ip Access Policy Manager
Published: 2019-02-26
Last modified: 2026-06-17

Description

On BIG-IP 11.5.1-11.6.3.2, 12.1.3.4-12.1.3.7, 13.0.0 HF1-13.1.1.1, and 14.0.0-14.0.0.2, Multi-Path TCP (MPTCP) does not protect against multiple zero length DATA_FINs in the reassembly queue, which can lead to an infinite loop in some circumstances.

Frequently asked questions

What is CVE-2019-6594?: On BIG-IP 11.5.1-11.6.3.2, 12.1.3.4-12.1.3.7, 13.0.0 HF1-13.1.1.1, and 14.0.0-14.0.0.2, Multi-Path TCP (MPTCP) does not protect against multiple zero length DATA_FINs in the reassembly queue, which can lead to an infinite loop in some circumstances.
How severe is CVE-2019-6594?: CVE-2019-6594 has a CVSS 3.x base score of 5.9, rated medium severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2019-6594 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (59th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2019-6594?: CVE-2019-6594 primarily affects F5 Big-ip Access Policy Manager. In total, 48 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2019-6594?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2019-6594 published?: CVE-2019-6594 was published on 2019-02-26 and last updated on 2026-06-17.

References

https://support.f5.com/csp/article/K91026261

Affected products (48)

cpe:2.3:a:f5:big-ip_access_policy_manager:*:*:*:*:*:*:*:*
cpe:2.3:a:f5:big-ip_access_policy_manager:13.0.0:hf1:*:*:*:*:*:*
cpe:2.3:a:f5:big-ip_access_policy_manager:13.0.0:hf2:*:*:*:*:*:*
cpe:2.3:a:f5:big-ip_access_policy_manager:13.0.0:hf3:*:*:*:*:*:*
cpe:2.3:a:f5:big-ip_local_traffic_manager:*:*:*:*:*:*:*:*
cpe:2.3:a:f5:big-ip_local_traffic_manager:13.0.0:hf1:*:*:*:*:*:*
cpe:2.3:a:f5:big-ip_local_traffic_manager:13.0.0:hf2:*:*:*:*:*:*
cpe:2.3:a:f5:big-ip_local_traffic_manager:13.0.0:hf3:*:*:*:*:*:*
cpe:2.3:a:f5:big-ip_advanced_firewall_manager:*:*:*:*:*:*:*:*
cpe:2.3:a:f5:big-ip_advanced_firewall_manager:13.0.0:hf1:*:*:*:*:*:*
cpe:2.3:a:f5:big-ip_advanced_firewall_manager:13.0.0:hf2:*:*:*:*:*:*
cpe:2.3:a:f5:big-ip_advanced_firewall_manager:13.0.0:hf3:*:*:*:*:*:*
cpe:2.3:a:f5:big-ip_analytics:*:*:*:*:*:*:*:*
cpe:2.3:a:f5:big-ip_analytics:13.0.0:hf1:*:*:*:*:*:*
cpe:2.3:a:f5:big-ip_analytics:13.0.0:hf2:*:*:*:*:*:*
cpe:2.3:a:f5:big-ip_analytics:13.0.0:hf3:*:*:*:*:*:*
cpe:2.3:a:f5:big-ip_application_security_manager:*:*:*:*:*:*:*:*
cpe:2.3:a:f5:big-ip_application_security_manager:13.0.0:hf1:*:*:*:*:*:*
cpe:2.3:a:f5:big-ip_application_security_manager:13.0.0:hf2:*:*:*:*:*:*
cpe:2.3:a:f5:big-ip_application_security_manager:13.0.0:hf3:*:*:*:*:*:*
cpe:2.3:a:f5:big-ip_domain_name_system:*:*:*:*:*:*:*:*
cpe:2.3:a:f5:big-ip_domain_name_system:13.0.0:hf1:*:*:*:*:*:*
cpe:2.3:a:f5:big-ip_domain_name_system:13.0.0:hf2:*:*:*:*:*:*
cpe:2.3:a:f5:big-ip_domain_name_system:13.0.0:hf3:*:*:*:*:*:*
cpe:2.3:a:f5:big-ip_edge_gateway:*:*:*:*:*:*:*:*
cpe:2.3:a:f5:big-ip_edge_gateway:13.0.0:hf1:*:*:*:*:*:*
cpe:2.3:a:f5:big-ip_edge_gateway:13.0.0:hf2:*:*:*:*:*:*
cpe:2.3:a:f5:big-ip_edge_gateway:13.0.0:hf3:*:*:*:*:*:*
cpe:2.3:a:f5:big-ip_fraud_protection_service:*:*:*:*:*:*:*:*
cpe:2.3:a:f5:big-ip_fraud_protection_service:13.0.0:hf1:*:*:*:*:*:*
cpe:2.3:a:f5:big-ip_fraud_protection_service:13.0.0:hf2:*:*:*:*:*:*
cpe:2.3:a:f5:big-ip_fraud_protection_service:13.0.0:hf3:*:*:*:*:*:*
cpe:2.3:a:f5:big-ip_global_traffic_manager:*:*:*:*:*:*:*:*
cpe:2.3:a:f5:big-ip_global_traffic_manager:13.0.0:hf1:*:*:*:*:*:*
cpe:2.3:a:f5:big-ip_global_traffic_manager:13.0.0:hf2:*:*:*:*:*:*
cpe:2.3:a:f5:big-ip_global_traffic_manager:13.0.0:hf3:*:*:*:*:*:*
cpe:2.3:a:f5:big-ip_link_controller:*:*:*:*:*:*:*:*
cpe:2.3:a:f5:big-ip_link_controller:13.0.0:hf1:*:*:*:*:*:*
cpe:2.3:a:f5:big-ip_link_controller:13.0.0:hf2:*:*:*:*:*:*
cpe:2.3:a:f5:big-ip_link_controller:13.0.0:hf3:*:*:*:*:*:*

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