How severe is CVE-2020-27718?

CVE-2020-27718 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2020-27718 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (60th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2020-27718?

CVE-2020-27718 primarily affects F5 Big-ip Advanced Web Application Firewall. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2020-27718?

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

When was CVE-2020-27718 published?

CVE-2020-27718 was published on 2020-12-24 and last updated on 2026-06-17.

CVE-2020-27718

CVE-2020-27718 is a high-severity vulnerability in F5 Big-ip Advanced Web Application Firewall with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low.

Key facts

Severity: High (CVSS 3.x base score 7.5)
CVSS v2: 5.0
EPSS exploit prediction: 1% (60th percentile)
Actively exploited: Not listed in CISA KEV
Affected product: F5 Big-ip Advanced Web Application Firewall
Published: 2020-12-24
Last modified: 2026-06-17

Description

When a BIG-IP ASM or Advanced WAF system running version 16.0.0-16.0.0.1, 15.1.0-15.1.0.5, 14.1.0-14.1.3, 13.1.0-13.1.3.4, 12.1.0-12.1.5.2, or 11.6.1-11.6.5.2 processes requests with JSON payload, an unusually large number of parameters can cause excessive CPU usage in the BIG-IP ASM bd process.

Frequently asked questions

What is CVE-2020-27718?: When a BIG-IP ASM or Advanced WAF system running version 16.0.0-16.0.0.1, 15.1.0-15.1.0.5, 14.1.0-14.1.3, 13.1.0-13.1.3.4, 12.1.0-12.1.5.2, or 11.6.1-11.6.5.2 processes requests with JSON payload, an unusually large number of parameters can cause excessive CPU usage in the BIG-IP ASM bd process.
How severe is CVE-2020-27718?: CVE-2020-27718 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2020-27718 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (60th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-27718?: CVE-2020-27718 primarily affects F5 Big-ip Advanced Web Application Firewall. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2020-27718?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2020-27718 published?: CVE-2020-27718 was published on 2020-12-24 and last updated on 2026-06-17.

References

https://support.f5.com/csp/article/K58102101

Affected products (2)

cpe:2.3:a:f5:big-ip_advanced_web_application_firewall:*:*:*:*:*:*:*:*
cpe:2.3:a:f5:big-ip_application_security_manager:*:*:*:*:*:*:*:*

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