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CVE-2021-22991

CRITICALCVSS 9.8/10Actively ExploitedEPSS 61.06%

Last modified

CVE-2021-22991 is a critical-severity vulnerability rated 9.8/10 on the CVSS scale. 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). CISA has confirmed active exploitation in the wild. EPSS estimates a 61.06% chance of exploitation in the next 30 days.

Description

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.

Metrics

CVSS 3.1
9.8/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS Probability
61.06%

99.0th percentile

Probability of exploitation in the next 30 days. Learn more

Exploitation Status

This vulnerability is listed in CISA’s Known Exploited Vulnerabilities catalog, confirming active exploitation in the wild. Federal agencies must remediate by .

Weakness Enumeration

Affected Software

VendorProductVersions
F5Big-Ip Access Policy Manager>= 12.1.0, < 12.1.5.3
F5Big-Ip Access Policy Manager>= 13.1.0, < 13.1.3.6
F5Big-Ip Access Policy Manager>= 14.1.0, < 14.1.4
F5Big-Ip Access Policy Manager>= 15.1.0, < 15.1.2.1
F5Big-Ip Access Policy Manager>= 16.0.0, < 16.0.1.1
F5Big-Ip Advanced Firewall Manager>= 12.1.0, < 12.1.5.3
F5Big-Ip Advanced Firewall Manager>= 13.1.0, < 13.1.3.6
F5Big-Ip Advanced Firewall Manager>= 14.1.0, < 14.1.4
F5Big-Ip Advanced Firewall Manager>= 15.1.0, < 15.1.2.1
F5Big-Ip Advanced Firewall Manager>= 16.0.0, < 16.0.1.1
F5Big-Ip Advanced Web Application Firewall>= 12.1.0, < 12.1.5.3
F5Big-Ip Advanced Web Application Firewall>= 13.1.0, < 13.1.3.6
F5Big-Ip Advanced Web Application Firewall>= 14.1.0, < 14.1.4
F5Big-Ip Advanced Web Application Firewall>= 15.1.0, < 15.1.2.1
F5Big-Ip Advanced Web Application Firewall>= 16.0.0, < 16.0.1.1
F5Big-Ip Analytics>= 12.1.0, < 12.1.5.3
F5Big-Ip Analytics>= 13.1.0, < 13.1.3.6
F5Big-Ip Analytics>= 14.1.0, < 14.1.4
F5Big-Ip Analytics>= 15.1.0, < 15.1.2.1
F5Big-Ip Analytics>= 16.0.0, < 16.0.1.1
F5Big-Ip Application Acceleration Manager>= 12.1.0, < 12.1.5.3
F5Big-Ip Application Acceleration Manager>= 13.1.0, < 13.1.3.6
F5Big-Ip Application Acceleration Manager>= 14.1.0, < 14.1.4
F5Big-Ip Application Acceleration Manager>= 15.1.0, < 15.1.2.1
F5Big-Ip Application Acceleration Manager>= 16.0.0, < 16.0.1.1
F5Big-Ip Application Security Manager>= 12.1.0, < 12.1.5.3
F5Big-Ip Application Security Manager>= 13.1.0, < 13.1.3.6
F5Big-Ip Application Security Manager>= 14.1.0, < 14.1.4
F5Big-Ip Application Security Manager>= 15.1.0, < 15.1.2.1
F5Big-Ip Application Security Manager>= 16.0.0, < 16.0.1.1
F5Big-Ip Ddos Hybrid Defender>= 12.1.0, < 12.1.5.3
F5Big-Ip Ddos Hybrid Defender>= 13.1.0, < 13.1.3.6
F5Big-Ip Ddos Hybrid Defender>= 14.1.0, < 14.1.4
F5Big-Ip Ddos Hybrid Defender>= 15.1.0, < 15.1.2.1
F5Big-Ip Ddos Hybrid Defender>= 16.0.0, < 16.0.1.1
F5Big-Ip Domain Name System>= 12.1.0, < 12.1.5.3
F5Big-Ip Domain Name System>= 13.1.0, < 13.1.3.6
F5Big-Ip Domain Name System>= 14.1.0, < 14.1.4
F5Big-Ip Domain Name System>= 15.1.0, < 15.1.2.1
F5Big-Ip Domain Name System>= 16.0.0, < 16.0.1.1
F5Big-Ip Fraud Protection Service>= 12.1.0, < 12.1.5.3
F5Big-Ip Fraud Protection Service>= 13.1.0, < 13.1.3.6
F5Big-Ip Fraud Protection Service>= 14.1.0, < 14.1.4
F5Big-Ip Fraud Protection Service>= 15.1.0, < 15.1.2.1
F5Big-Ip Fraud Protection Service>= 16.0.0, < 16.0.1.1
F5Big-Ip Global Traffic Manager>= 12.1.0, < 12.1.5.3
F5Big-Ip Global Traffic Manager>= 13.1.0, < 13.1.3.6
F5Big-Ip Global Traffic Manager>= 14.1.0, < 14.1.4
F5Big-Ip Global Traffic Manager>= 15.1.0, < 15.1.2.1
F5Big-Ip Global Traffic Manager>= 16.0.0, < 16.0.1.1

Showing 50 of 70 affected configurations. See NVD for the full list.

References

Timeline

Published
Last Modified
Status
Analyzed

Frequently Asked Questions

What is CVE-2021-22991?
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.
How severe is CVE-2021-22991?
CVE-2021-22991 has a CVSS score of 9.8/10 (CRITICAL severity). The EPSS model estimates a 61.06% probability of exploitation in the next 30 days. This vulnerability is listed in CISA's Known Exploited Vulnerabilities catalog.
How do I fix CVE-2021-22991?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST