{"id":"CVE-2021-22991","aliases":["EUVD-2021-10109","GHSA-6w8r-pjm3-q7x7"],"status":"published","title":"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...","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":{"version":"3.1","score":9.8,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","level":"critical","assessor":"primary","from":"nvd"},"epss":{"day":"2026-11-12","score":0.62421,"percentile":0.99199,"model":"v2026.06.15"},"facts":{"in_kev":true,"known_exploited":true,"public_exploit":false,"fix_available":false},"cwes":["CWE-119","CWE-120","CWE-20"],"published":"2021-03-31T17:23:14Z","modified":"2026-06-17T03:38:10Z","kev":{"date_added":"2022-01-18","due_date":"2022-02-01","required_action":"Apply updates per vendor instructions.","known_ransomware_use":"Unknown"},"exploitation":[{"source":"euvd","since":"2022-01-18"},{"source":"kev","since":"2022-01-18"}],"products":[{"vendor":"f5","product":"big-ip"},{"vendor":"f5","product":"big-ip traffic management microkernel"},{"vendor":"f5","product":"big-ip_access_policy_manager"},{"vendor":"f5","product":"big-ip_advanced_firewall_manager"},{"vendor":"f5","product":"big-ip_advanced_web_application_firewall"},{"vendor":"f5","product":"big-ip_analytics"},{"vendor":"f5","product":"big-ip_application_acceleration_manager"},{"vendor":"f5","product":"big-ip_application_security_manager"},{"vendor":"f5","product":"big-ip_ddos_hybrid_defender"},{"vendor":"f5","product":"big-ip_domain_name_system"},{"vendor":"f5","product":"big-ip_fraud_protection_service"},{"vendor":"f5","product":"big-ip_global_traffic_manager"},{"vendor":"f5","product":"big-ip_link_controller"},{"vendor":"f5","product":"big-ip_local_traffic_manager"},{"vendor":"f5","product":"big-ip_policy_enforcement_manager"},{"vendor":"f5","product":"ssl_orchestrator"}],"references":[{"url":"https://support.f5.com/csp/article/K56715231","tags":["x_refsource_MISC","x_transferred","Vendor Advisory"]},{"url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-22991","tags":["government-resource","US Government Resource"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2021-22991"},{"url":"https://github.com/advisories/GHSA-6w8r-pjm3-q7x7"}],"sources":{"cve":[{"id":"CVE-2021-22991","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.","status":"published","published":"2021-03-31T17:23:14Z","modified":"2025-10-21T23:25:50.646Z","cvss":[{"version":"3.1","score":9.8,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","level":"critical","assessor":"adp"}],"cwes":["CWE-119"],"updated_at":"2026-11-02T14:32:58.028461Z"}],"euvd":[{"id":"EUVD-2021-10109","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.","status":"published","published":"2021-03-31T17:23:14Z","modified":"2025-10-21T23:25:50Z","cvss":[{"version":"3.1","score":9.8,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","level":"critical"}],"exploited_since":"2022-01-18","updated_at":"2026-11-02T20:31:25.308373Z"}],"ghsa":[{"id":"GHSA-6w8r-pjm3-q7x7","title":"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...","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.","status":"published","published":"2022-05-24T17:45:57Z","modified":"2025-10-22T00:33:09Z","cvss":[{"version":"3.1","score":9.8,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","level":"critical"}],"cwes":["CWE-20","CWE-119","CWE-120"],"updated_at":"2026-11-02T15:04:07.67458Z"}],"kev":[{"id":"CVE-2021-22991","title":"F5 BIG-IP Traffic Management Microkernel Buffer Overflow","description":"The Traffic Management Microkernel of BIG-IP ASM Risk Engine has a buffer overflow vulnerability, leading to a bypassing of URL-based access controls.","cwes":["CWE-119"],"kev":{"date_added":"2022-01-18","due_date":"2022-02-01","required_action":"Apply updates per vendor instructions.","known_ransomware_use":"Unknown"},"updated_at":"2026-11-02T17:00:16.541131Z"}],"nvd":[{"id":"CVE-2021-22991","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.","status":"published","published":"2021-03-31T18:15:14.787Z","modified":"2026-06-17T03:38:10.083Z","cvss":[{"version":"3.1","score":9.8,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","level":"critical","assessor":"primary"},{"version":"3.1","score":9.8,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","level":"critical","assessor":"secondary"},{"version":"2.0","score":6.8,"vector":"AV:N/AC:M/Au:N/C:P/I:P/A:P","level":"medium","assessor":"primary"}],"cwes":["CWE-119"],"updated_at":"2026-11-02T14:06:51.197859Z"}]}}