--- 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' --- ## Overview 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. ## 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` ## Remediation Upgrade past the affected range: - `essbase 21.3` - `sinec_infrastructure_network_services 1.0.1.1` - `universal_forwarder 9.0.6`