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CVE-2021-22991: F5 BIG-IP Traffic Management Microkernel Buffer Overflow

CVE-2021-22991 is rated critical with a CVSS v3.1 base score of 9.8 and affects F5 BIG-IP Traffic Management Microkernel, along with 14 other products in NVD’s configuration data. Per its scoring, it can be exploited over the network, without authentication, without any user interaction. The scored impact on confidentiality, integrity and availability is the highest available. CISA added it to its Known Exploited Vulnerabilities catalog on 2022-01-18, which means exploitation in the wild has been observed.

Vulnerability 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.

Severity breakdown

CVSS v3.1 9.8: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

  • Attack vector: Network. Exploitable remotely over the network, with no need for local or physical access.
  • Attack complexity: Low. No special conditions; the attack can be repeated reliably.
  • Privileges required: None. No account or prior access is needed.
  • User interaction: None. No action from any user is needed.
  • Scope: Unchanged. Impact stays within the vulnerable component.
  • Confidentiality impact: High. Total loss of confidentiality; sensitive data can be fully disclosed.
  • Integrity impact: High. Total loss of integrity; data or system state can be fully modified.
  • Availability impact: High. Total loss of availability; the component can be shut down.

Underlying weakness

CWE-119: Improper Restriction of Operations within the Bounds of a Memory Buffer

The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary.

Affected products

  • F5 Big IP Access Policy Manager: from 12.1.0 before 12.1.5.3; from 13.1.0 before 13.1.3.6; from 14.1.0 before 14.1.4; from 15.1.0 before 15.1.2.1; from 16.0.0 before 16.0.1.1
  • F5 Big IP Advanced Firewall Manager: from 12.1.0 before 12.1.5.3; from 13.1.0 before 13.1.3.6; from 14.1.0 before 14.1.4; from 15.1.0 before 15.1.2.1; from 16.0.0 before 16.0.1.1
  • F5 Big IP Advanced Web Application Firewall: from 12.1.0 before 12.1.5.3; from 13.1.0 before 13.1.3.6; from 14.1.0 before 14.1.4; from 15.1.0 before 15.1.2.1; from 16.0.0 before 16.0.1.1
  • F5 Big IP Analytics: from 12.1.0 before 12.1.5.3; from 13.1.0 before 13.1.3.6; from 14.1.0 before 14.1.4; from 15.1.0 before 15.1.2.1; from 16.0.0 before 16.0.1.1
  • F5 Big IP Application Acceleration Manager: from 12.1.0 before 12.1.5.3; from 13.1.0 before 13.1.3.6; from 14.1.0 before 14.1.4; from 15.1.0 before 15.1.2.1; from 16.0.0 before 16.0.1.1
  • F5 Big IP Application Security Manager: from 12.1.0 before 12.1.5.3; from 13.1.0 before 13.1.3.6; from 14.1.0 before 14.1.4; from 15.1.0 before 15.1.2.1; from 16.0.0 before 16.0.1.1
  • F5 Big IP Ddos Hybrid Defender: from 12.1.0 before 12.1.5.3; from 13.1.0 before 13.1.3.6; from 14.1.0 before 14.1.4; from 15.1.0 before 15.1.2.1; from 16.0.0 before 16.0.1.1
  • F5 Big IP Domain Name System: from 12.1.0 before 12.1.5.3; from 13.1.0 before 13.1.3.6; from 14.1.0 before 14.1.4; from 15.1.0 before 15.1.2.1; from 16.0.0 before 16.0.1.1
  • F5 Big IP Fraud Protection Service: from 12.1.0 before 12.1.5.3; from 13.1.0 before 13.1.3.6; from 14.1.0 before 14.1.4; from 15.1.0 before 15.1.2.1; from 16.0.0 before 16.0.1.1
  • F5 Big IP Global Traffic Manager: from 12.1.0 before 12.1.5.3; from 13.1.0 before 13.1.3.6; from 14.1.0 before 14.1.4; from 15.1.0 before 15.1.2.1; from 16.0.0 before 16.0.1.1
  • F5 Big IP Link Controller: from 12.1.0 before 12.1.5.3; from 13.1.0 before 13.1.3.6; from 14.1.0 before 14.1.4; from 15.1.0 before 15.1.2.1; from 16.0.0 before 16.0.1.1
  • F5 Big IP Local Traffic Manager: from 12.1.0 before 12.1.5.3; from 13.1.0 before 13.1.3.6; from 14.1.0 before 14.1.4; from 15.1.0 before 15.1.2.1; from 16.0.0 before 16.0.1.1
  • F5 Big IP Policy Enforcement Manager: from 12.1.0 before 12.1.5.3; from 13.1.0 before 13.1.3.6; from 14.1.0 before 14.1.4; from 15.1.0 before 15.1.2.1; from 16.0.0 before 16.0.1.1
  • F5 SSL Orchestrator: from 12.1.0 before 12.1.5.3; from 13.1.0 before 13.1.3.6; from 14.1.0 before 14.1.4; from 15.1.0 before 15.1.2.1; from 16.0.0 before 16.0.1.1

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