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Vulnerabilities

Vulnerability · CVE-2021-22901

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 Jun 11, 2021 · catalog updated Oct 14, 2026 · curl 7.75.0 through 7.76.1

Check this week

CVE-2021-22901 is not in CISA KEV. FIRST estimates a 63.53% chance of exploitation in the next 30 days. Check whether you run curl 7.75.0 through 7.76.1.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (curl 7.75.0 through 7.76.1).
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
High8.1
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
63.53%
Remediation
Advisory link
Affected products
cpe haxx/curl · cpe netapp/active iq unified manager · cpe netapp/h300e firmware · cpe netapp/h300s firmware · cpe netapp/hci compute node firmware · cpe oracle/communications cloud native core binding support function

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.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • cpe haxx/curlversion unspecified
  • cpe netapp/active iq unified managerversion unspecified
  • cpe netapp/h300e firmwareversion unspecified
  • cpe netapp/h300s firmwareversion unspecified
  • cpe netapp/hci compute node firmwareversion unspecified
  • cpe oracle/communications cloud native core binding support function1.11.0
  • cpe oracle/communications cloud native core network function cloud native environment1.10.0
  • cpe oracle/communications cloud native core network repository function1.15.0
  • cpe oracle/communications cloud native core network repository function1.15.1
  • cpe oracle/communications cloud native core network slice selection function1.8.0
  • cpe oracle/communications cloud native core service communication proxy1.15.0
  • cpe oracle/essbaseversion unspecified

How to fix CVE-2021-22901

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

CVE-2021-22901 is not in CISA KEV. FIRST estimates a 63.53% chance of exploitation in the next 30 days. Check whether you run curl 7.75.0 through 7.76.1.

Which versions are affected?

Compare what you have installed with oracle/communications cloud native core binding support function 1.11.0; oracle/communications cloud native core network function cloud native environment 1.10.0; oracle/communications cloud native core network repository function 1.15.0; oracle/communications cloud native core network repository function 1.15.1. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-416: Use After Free. EPSS 63.53%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Jun 11, 2021 · NIST NVD

    Detected

    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

  2. Oct 14, 2026 · NIST NVD

    Updated

    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

Sources

  • CVE.orgVulnerability recordCVE-2021-22901

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2021-22901

    30-day exploitation probability 63.5%

    first.org
  • NIST NVDVulnerability recordCVE-2021-22901

    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 executio

    nvd.nist.gov

References

Freshness

Last verified in this catalog Oct 15, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.