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Vulnerabilities/CVE-2021-22901Public Intelligence Dossier
Source: haxx · Limited verification•Last verified: •Collection Degraded
CVE-2021-22901Unknown / EvaluatingHIGH (raw)CVSS 8.1CWE-416

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

Published: 11 Jun 2021•Last updated: 14 Oct 2026, 04:46 PM IST•Source identifier: support@hackerone.com
Dossier completeness: source-provided sections 2 / 3 · rule guidance available. Missing source facts count as incomplete.
Official source
CISA KEV catalog
Unknown
KEV status was not determined.
CVSS score
8.1HIGH (raw)
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
Metric sourcenvd@nist.gov
EPSS probability
63.5%0.635
Percentile99th
Weakness type
CWE-416
No further CWE recorded
Remediation
Patch status unknown
No fixed version or KB recorded

Why It Matters

Analysis dossier

Why It Matters

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.

SOC priority

High

Actively exploited

Unknown

Publicly disclosed

Unknown

Risk basis: Microsoft or Microsoft-managed product relevance; HIGH severity; No confirmed exploitation signal in current enrichment

Affected Products & Remediation

26 source-backed products
Affected products and versions (source)
  • haxx curl · >= 7.75.0 <= 7.76.1 · NVD CPE · Source
  • oracle communications cloud native core binding support function · 1.11.0 · NVD CPE · Source
  • oracle communications cloud native core network function cloud native environment · 1.10.0 · NVD CPE · Source
  • oracle communications cloud native core network repository function · 1.15.0; 1.15.1 · NVD CPE · Source
  • oracle communications cloud native core network slice selection function · 1.8.0 · NVD CPE · Source
  • oracle communications cloud native core service communication proxy · 1.15.0 · NVD CPE · Source
  • oracle essbase · < 11.1.2.4.047; >= 21.0 < 21.3 · NVD CPE · Source
  • oracle mysql server · <= 5.7.34; >= 8.0.0 <= 8.0.25 · NVD CPE · Source
  • netapp active iq unified manager · version range not provided by source · NVD CPE · Source
  • netapp cloud backup · version range not provided by source · NVD CPE · Source
  • netapp oncommand insight · version range not provided by source · NVD CPE · Source
  • netapp oncommand workflow automation · version range not provided by source · NVD CPE · Source
  • netapp snapcenter · version range not provided by source · NVD CPE · Source
  • netapp solidfire\, enterprise sds \& hci storage node · version range not provided by source · NVD CPE · Source
  • netapp solidfire \& hci management node · version range not provided by source · NVD CPE · Source
  • netapp solidfire baseboard management controller firmware · version range not provided by source · NVD CPE · Source
  • netapp hci compute node firmware · version range not provided by source · NVD CPE · Source
  • netapp h300e firmware · version range not provided by source · NVD CPE · Source
  • netapp h300s firmware · version range not provided by source · NVD CPE · Source
  • netapp h410s firmware · version range not provided by source · NVD CPE · Source
  • netapp h500e firmware · version range not provided by source · NVD CPE · Source
  • netapp h500s firmware · version range not provided by source · NVD CPE · Source
  • netapp h700e firmware · version range not provided by source · NVD CPE · Source
  • netapp h700s firmware · version range not provided by source · NVD CPE · Source
  • siemens sinec infrastructure network services · < 1.0.1.1 · NVD CPE · Source
  • splunk universal forwarder · >= 8.2.0 < 8.2.12; >= 9.0.0 < 9.0.6; 9.1.0 · NVD CPE · Source
NVD applicability prerequisites: cpe:2.3:h:netapp:hci_compute_node:-:*:*:*:*:*:*:*, cpe:2.3:h:netapp:h300e:-:*:*:*:*:*:*:*, cpe:2.3:h:netapp:h300s:-:*:*:*:*:*:*:*, cpe:2.3:h:netapp:h410s:-:*:*:*:*:*:*:*, cpe:2.3:h:netapp:h500e:-:*:*:*:*:*:*:*, cpe:2.3:h:netapp:h500s:-:*:*:*:*:*:*:*, cpe:2.3:h:netapp:h700e:-:*:*:*:*:*:*:*, cpe:2.3:h:netapp:h700s:-:*:*:*:*:*:*:*. These are conditions, not proof that an environment is exposed or unaffected.
Recorded patch / KBNot provided by source

Vendor or catalog guidance (source)

Not provided by source

Known exploitation (source facts)

Only what a source states. Unknown means no source has said either way; it is not "not exploited".

CISA KEV
Unknown
Exploited (source statement)
Unknown
Publicly disclosed (source)
Unknown

Suggested hunting (rule-based inference)

SecOps Signal recommendation (rule-based inference). These steps are hunting hypotheses from the vulnerability class; they do not state or imply that exploitation occurred here or anywhere.

Matched network-unauthenticated (CVSS AV:N, CVSS PR:N, CVSS UI:N)

Exposure

  1. Identify devices reporting this CVE and note which expose the affected service to untrusted networks.Telemetry: DeviceTvmSoftwareVulnerabilities · A network-reachable, no-privilege vector makes internet-facing instances the first exposure question. · Rule network-unauthenticated

Exploitation evidence

  1. Review inbound connections to the affected service from unexpected sources since the advisory date.Telemetry: DeviceNetworkEvents · Hunting hypothesis from the CVSS vector; it does not show that exploitation occurred. · Rule network-unauthenticated

Response

  1. Confirm the source-stated update is installed and the CVE is no longer reported.Telemetry: DeviceTvmSoftwareVulnerabilities · A follow-up inventory check verifies remediation. · Rule network-unauthenticated

CISA KEV Record

CISA KEV status was not determined for this record.

Change History & Source Data

— No recorded material change

CNA / source
support@hackerone.com
Record status · verification
UPDATED · NVD API
CPE
cpe:2.3:a:haxx:curl:*:*:*:*:*:*:*:*, cpe:2.3:a:oracle:communications_cloud_native_core_binding_support_function:1.11.0:*:*:*:*:*:*:*, cpe:2.3:a:oracle:communications_cloud_native_core_network_function_cloud_native_environment:1.10.0:*:*:*:*:*:*:*, cpe:2.3:a:oracle:communications_cloud_native_core_network_repository_function:1.15.0:*:*:*:*:*:*:*, cpe:2.3:a:oracle:communications_cloud_native_core_network_repository_function:1.15.1:*:*:*:*:*:*:*, cpe:2.3:a:oracle:communications_cloud_native_core_network_slice_selection_function:1.8.0:*:*:*:*:*:*:*, cpe:2.3:a:oracle:communications_cloud_native_core_service_communication_proxy:1.15.0:*:*:*:*:*:*:*, cpe:2.3:a:oracle:essbase:*:*:*:*:*:*:*:*, cpe:2.3:a:oracle:mysql_server:*:*:*:*:*:*:*:*, cpe:2.3:a:netapp:active_iq_unified_manager:-:*:*:*:*:vsphere:*:*

Evidence & Provenance

3 public sources
cert-portal.siemens.comSource recordnvd.nist.govSource recordcert-portal.siemens.comSource record

Linked by the query's stored exact CVE association. Review required tables and validation status before use.

Detection Hunting Query
Target: DeviceTvmSoftwareVulnerabilities•Defender XDR
Detect endpoints exposed to CVE-2021-22901
Purpose: Exposure assessment (Category: Exposure Check)Why linked: Query metadata names CVE-2021-22901
DeviceTvmSoftwareVulnerabilities| where CveId == "CVE-2021-22901"| project DeviceId, DeviceName, OSPlatform, OSVersion, SoftwareVendor, SoftwareName, SoftwareVersion, CveId, VulnerabilitySeverityLevel, RecommendedSecurityUpdate, RecommendedSecurityUpdateId| sort by VulnerabilitySeverityLevel desc
Schema Checked · Not runtime validatedSource: SecOps Signal deterministic template · Limited verificationStatic screening: Passed structure and schema checks; tenant execution is not verified.
Open KQL Library

Correlated briefings

— No published briefing references this CVE

SecOps Signal surfaces public advisory facts only. A missing value means the source has not published it, not that your environment is unaffected. No tenant inventory is connected.