{"cve":"CVE-2021-22999","nvd":{"published":"2021-03-31T18:15:15.160","modified":"2026-06-17T03:38:11.030","status":"Modified","description":"On versions 15.0.x before 15.1.0 and 14.1.x before 14.1.4, the BIG-IP system provides an option to connect HTTP/2 clients to HTTP/1.x servers. When a client is slow to accept responses and it closes a connection prematurely, the BIG-IP system may indefinitely retain some streams unclosed. Note: Software versions which have reached End of Software Development (EoSD) are not evaluated.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","score":7.5},"cwes":[],"references":["https://support.f5.com/csp/article/K02333782","https://support.f5.com/csp/article/K02333782"],"products":["f5:big-ip_access_policy_manager","f5:big-ip_advanced_firewall_manager","f5:big-ip_advanced_web_application_firewall","f5:big-ip_analytics","f5:big-ip_application_acceleration_manager","f5:big-ip_application_security_manager","f5:big-ip_ddos_hybrid_defender","f5:big-ip_domain_name_system","f5:big-ip_fraud_protection_service","f5:big-ip_global_traffic_manager","f5:big-ip_link_controller","f5:big-ip_local_traffic_manager","f5:big-ip_policy_enforcement_manager","f5:ssl_orchestrator"],"source":"nvd","synced_at":"2026-10-19T21:17:01.373894544+00:00"},"epss":{"cve":"CVE-2021-22999","score":0.00995,"percentile":0.62681,"date":"2026-10-31"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}