{"cve":"CVE-2021-22901","nvd":{"published":"2021-06-11T16:15:11.120","modified":"2026-10-14T11:16:53.157","status":"Modified","description":"curl 7.75.0 through 7.76.1 suffers from a use-after-free vulnerability resulting in already freed memory being used when a TLS 1.3 session ticket arrives over a connection. A malicious server can use this in rare unfortunate circumstances to potentially reach remote code execution in the client. When libcurl at run-time sets up support for TLS 1.3 session tickets on a connection using OpenSSL, it stores pointers to the transfer in-memory object for later retrieval when a session ticket arrives. If the connection is used by multiple transfers (like with a reused HTTP/1.1 connection or multiplexed HTTP/2 connection) that first transfer object might be freed before the new session is established on that connection and then the function will access a memory buffer that might be freed. When using that memory, libcurl might even call a function pointer in the object, making it possible for a remote code execution if the server could somehow manage to get crafted memory content into the correct place in memory.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H","score":8.1},"cwes":["CWE-416"],"references":["https://cert-portal.siemens.com/productcert/pdf/ssa-389290.pdf","https://cert-portal.siemens.com/productcert/pdf/ssa-732250.pdf","https://curl.se/docs/CVE-2021-22901.html","https://github.com/curl/curl/commit/7f4a9a9b2a49547eae24d2e19bc5c346e9026479","https://hackerone.com/reports/1180380"],"products":["haxx:curl","netapp:active_iq_unified_manager","netapp:cloud_backup","netapp:h300e_firmware","netapp:h300s_firmware","netapp:h410s_firmware","netapp:h500e_firmware","netapp:h500s_firmware","netapp:h700e_firmware","netapp:h700s_firmware","netapp:hci_compute_node_firmware","netapp:oncommand_insight","netapp:oncommand_workflow_automation","netapp:snapcenter","netapp:solidfire\\,_enterprise_sds_\\&_hci_storage_node","netapp:solidfire_\\&_hci_management_node","netapp:solidfire_baseboard_management_controller_firmware","oracle:communications_cloud_native_core_binding_support_function","oracle:communications_cloud_native_core_network_function_cloud_native_environment","oracle:communications_cloud_native_core_network_repository_function","oracle:communications_cloud_native_core_network_slice_selection_function","oracle:communications_cloud_native_core_service_communication_proxy","oracle:essbase","oracle:mysql_server","siemens:sinec_infrastructure_network_services","splunk:universal_forwarder"],"source":"nvd","synced_at":"2026-10-19T21:20:07.141963181+00:00"},"epss":{"cve":"CVE-2021-22901","score":0.63531,"percentile":0.99206,"date":"2026-10-25"},"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."]}