How severe is CVE-2018-15311?

CVE-2018-15311 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-2018-15311 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (70th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2018-15311?

CVE-2018-15311 primarily affects F5 Big-ip Local Traffic Manager. In total, 13 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2018-15311?

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

When was CVE-2018-15311 published?

CVE-2018-15311 was published on 2018-10-10 and last updated on 2026-06-17.

CVE-2018-15311

CVE-2018-15311 is a medium-severity vulnerability in F5 Big-ip Local Traffic 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.

Key facts

Severity: Medium (CVSS 3.x base score 5.9)
CVSS v2: 4.3
EPSS exploit prediction: 1% (70th percentile)
Actively exploited: Not listed in CISA KEV
Affected product: F5 Big-ip Local Traffic Manager
Published: 2018-10-10
Last modified: 2026-06-17

Description

When F5 BIG-IP 13.0.0-13.1.0.5, 12.1.0-12.1.3.5, 11.6.0-11.6.3.2, or 11.5.1-11.5.6 is processing specially crafted TCP traffic with the Large Receive Offload (LRO) feature enabled, TMM may crash, leading to a failover event. This vulnerability is not exposed unless LRO is enabled, so most affected customers will be on 13.1.x. LRO has been available since 11.4.0 but is not enabled by default until 13.1.0.

Frequently asked questions

What is CVE-2018-15311?: When F5 BIG-IP 13.0.0-13.1.0.5, 12.1.0-12.1.3.5, 11.6.0-11.6.3.2, or 11.5.1-11.5.6 is processing specially crafted TCP traffic with the Large Receive Offload (LRO) feature enabled, TMM may crash, leading to a failover event. This vulnerability is not exposed unless LRO is enabled, so most affected customers will be on 13.1.x. LRO has been available since 11.4.0 but is not enabled by default until 13.1.0.
How severe is CVE-2018-15311?: CVE-2018-15311 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-2018-15311 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (70th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2018-15311?: CVE-2018-15311 primarily affects F5 Big-ip Local Traffic Manager. In total, 13 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2018-15311?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2018-15311 published?: CVE-2018-15311 was published on 2018-10-10 and last updated on 2026-06-17.

References

https://support.f5.com/csp/article/K07550539

Affected products (13)

cpe:2.3:a:f5:big-ip_local_traffic_manager:*:*:*:*:*:*:*:*
cpe:2.3:a:f5:big-ip_application_acceleration_manager:*:*:*:*:*:*:*:*
cpe:2.3:a:f5:big-ip_advanced_firewall_manager:*:*:*:*:*:*:*:*
cpe:2.3:a:f5:big-ip_analytics:*:*:*:*:*:*:*:*
cpe:2.3:a:f5:big-ip_access_policy_manager:*:*:*:*:*:*:*:*
cpe:2.3:a:f5:big-ip_application_security_manager:*:*:*:*:*:*:*:*
cpe:2.3:a:f5:big-ip_domain_name_system:*:*:*:*:*:*:*:*
cpe:2.3:a:f5:big-ip_edge_gateway:*:*:*:*:*:*:*:*
cpe:2.3:a:f5:big-ip_fraud_protection_service:*:*:*:*:*:*:*:*
cpe:2.3:a:f5:big-ip_global_traffic_manager:*:*:*:*:*:*:*:*
cpe:2.3:a:f5:big-ip_link_controller:*:*:*:*:*:*:*:*
cpe:2.3:a:f5:big-ip_policy_enforcement_manager:*:*:*:*:*:*:*:*
cpe:2.3:a:f5:big-ip_webaccelerator:*:*:*:*:*:*:*:*

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