{"id":"CVE-2021-22901","title":"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","summary":"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 circumstance…","severity":"high","cvss":8.1,"cvssVector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H","cwe":["CWE-416","CWE-416"],"vendor":"haxx","product":"curl","affected":["curl >= 7.75.0, <= 7.76.1","communications_cloud_native_core_binding_support_function = 1.11.0","communications_cloud_native_core_network_function_cloud_native_environment = 1.10.0","communications_cloud_native_core_network_repository_function = 1.15.0","communications_cloud_native_core_network_repository_function = 1.15.1","communications_cloud_native_core_network_slice_selection_function = 1.8.0","communications_cloud_native_core_service_communication_proxy = 1.15.0","essbase < 11.1.2.4.047","essbase >= 21.0, < 21.3","mysql_server <= 5.7.34","mysql_server >= 8.0.0, <= 8.0.25","active_iq_unified_manager","cloud_backup","oncommand_insight","oncommand_workflow_automation","snapcenter","solidfire,_enterprise_sds_&_hci_storage_node","solidfire_&_hci_management_node","solidfire_baseboard_management_controller_firmware","hci_compute_node_firmware","h300e_firmware","h300s_firmware","h410s_firmware","h500e_firmware","h500s_firmware","h700e_firmware","h700s_firmware","sinec_infrastructure_network_services < 1.0.1.1","universal_forwarder >= 8.2.0, < 8.2.12","universal_forwarder >= 9.0.0, < 9.0.6","universal_forwarder = 9.1.0"],"patched":["essbase 21.3","sinec_infrastructure_network_services 1.0.1.1","universal_forwarder 9.0.6"],"published":"2021-06-11","updated":"2026-10-08","sourceUpdated":"2026-10-08T21:17:33.723","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2021-22901","references":[{"url":"https://cert-portal.siemens.com/productcert/pdf/ssa-389290.pdf","label":"support@hackerone.com"},{"url":"https://cert-portal.siemens.com/productcert/pdf/ssa-732250.pdf","label":"support@hackerone.com"},{"url":"https://curl.se/docs/CVE-2021-22901.html","label":"support@hackerone.com"},{"url":"https://github.com/curl/curl/commit/7f4a9a9b2a49547eae24d2e19bc5c346e9026479","label":"support@hackerone.com"},{"url":"https://hackerone.com/reports/1180380","label":"support@hackerone.com"},{"url":"https://security.netapp.com/advisory/ntap-20210723-0001/","label":"support@hackerone.com"},{"url":"https://security.netapp.com/advisory/ntap-20210727-0007/","label":"support@hackerone.com"},{"url":"https://www.oracle.com//security-alerts/cpujul2021.html","label":"support@hackerone.com"},{"url":"https://www.oracle.com/security-alerts/cpuapr2022.html","label":"support@hackerone.com"},{"url":"https://www.oracle.com/security-alerts/cpujan2022.html","label":"support@hackerone.com"},{"url":"https://cert-portal.siemens.com/productcert/pdf/ssa-389290.pdf","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://cert-portal.siemens.com/productcert/pdf/ssa-732250.pdf","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://curl.se/docs/CVE-2021-22901.html","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://github.com/curl/curl/commit/7f4a9a9b2a49547eae24d2e19bc5c346e9026479","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://hackerone.com/reports/1180380","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://security.netapp.com/advisory/ntap-20210723-0001/","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://security.netapp.com/advisory/ntap-20210727-0007/","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.oracle.com//security-alerts/cpujul2021.html","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.oracle.com/security-alerts/cpuapr2022.html","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.oracle.com/security-alerts/cpujan2022.html","label":"af854a3a-2127-422b-91ae-364da2661108"}],"tags":["nvd"],"epss":0.60122,"epssPercentile":0.99116,"ingestedAt":"2026-10-08T22:11:53.736Z","slug":"CVE-2021-22901","body":"## Overview\n\ncurl 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.\n\n## Affected\n\n- `curl >= 7.75.0, <= 7.76.1`\n- `communications_cloud_native_core_binding_support_function = 1.11.0`\n- `communications_cloud_native_core_network_function_cloud_native_environment = 1.10.0`\n- `communications_cloud_native_core_network_repository_function = 1.15.0`\n- `communications_cloud_native_core_network_repository_function = 1.15.1`\n- `communications_cloud_native_core_network_slice_selection_function = 1.8.0`\n- `communications_cloud_native_core_service_communication_proxy = 1.15.0`\n- `essbase < 11.1.2.4.047`\n- `essbase >= 21.0, < 21.3`\n- `mysql_server <= 5.7.34`\n- `mysql_server >= 8.0.0, <= 8.0.25`\n- `active_iq_unified_manager`\n- `cloud_backup`\n- `oncommand_insight`\n- `oncommand_workflow_automation`\n- `snapcenter`\n- `solidfire,_enterprise_sds_&_hci_storage_node`\n- `solidfire_&_hci_management_node`\n- `solidfire_baseboard_management_controller_firmware`\n- `hci_compute_node_firmware`\n- `h300e_firmware`\n- `h300s_firmware`\n- `h410s_firmware`\n- `h500e_firmware`\n- `h500s_firmware`\n- `h700e_firmware`\n- `h700s_firmware`\n- `sinec_infrastructure_network_services < 1.0.1.1`\n- `universal_forwarder >= 8.2.0, < 8.2.12`\n- `universal_forwarder >= 9.0.0, < 9.0.6`\n- `universal_forwarder = 9.1.0`\n\n## Remediation\n\nUpgrade past the affected range:\n\n- `essbase 21.3`\n- `sinec_infrastructure_network_services 1.0.1.1`\n- `universal_forwarder 9.0.6`","depth":"twilight","depthScore":57,"depthScoreParts":{"impact":44.6,"likelihood":12,"exploitation":0,"ransomware":0},"changes":[]}