CVE-2021-22976

CVE-2021-22976 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

Description

On BIG-IP Advanced WAF and ASM version 16.0.x before 16.0.1.1, 15.1.x before 15.1.2, 14.1.x before 14.1.3.1, 13.1.x before 13.1.3.6, and all 12.1.x versions, when the BIG-IP ASM system processes WebSocket requests with JSON payloads, an unusually large number of parameters can cause excessive CPU usage in the BIG-IP ASM bd process. Note: Software versions which have reached End of Software Development (EoSD) are not evaluated.

Frequently asked questions

What is CVE-2021-22976?
On BIG-IP Advanced WAF and ASM version 16.0.x before 16.0.1.1, 15.1.x before 15.1.2, 14.1.x before 14.1.3.1, 13.1.x before 13.1.3.6, and all 12.1.x versions, when the BIG-IP ASM system processes WebSocket requests with JSON payloads, an unusually large number of parameters can cause excessive CPU usage in the BIG-IP ASM bd process. Note: Software versions which have reached End of Software Development (EoSD) are not evaluated.
How severe is CVE-2021-22976?
CVE-2021-22976 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-2021-22976 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (57th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-22976?
CVE-2021-22976 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-2021-22976?
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-2021-22976 published?
CVE-2021-22976 was published on 2021-02-12 and last updated on 2026-06-17.

References

Affected products (2)

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