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Vulnerabilities

Vulnerability · CVE-2021-22945

When sending data to an MQTT server, libcurl <= 7.73.0 and 7.78.0 could in some circumstances erroneously keep a pointer to an already freed memory area and both use t…

Published Sep 23, 2021 · catalog updated Oct 14, 2026 · the affected product

Check if you run it

No confirmed exploitation is on record for CVE-2021-22945. EPSS is 6.68%. Act only if a listed version of the affected product is installed.

Gaps on this record

  • No plain product name is stored. The page cannot tell you which product to check.
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
Critical9.1
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
6.68%
Remediation
Version ranges on file
Affected products
cpe fedoraproject/fedora · cpe haxx/libcurl · cpe netapp/cloud backup · cpe netapp/clustered data ontap · cpe netapp/h300e firmware · cpe netapp/h300s firmware

When sending data to an MQTT server, libcurl <= 7.73.0 and 7.78.0 could in some circumstances erroneously keep a pointer to an already freed memory area and both use that again in a subsequent call to send data and also free it *again*.

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 fedoraproject/fedora33
  • cpe fedoraproject/fedora35
  • cpe haxx/libcurlversion unspecified
  • cpe netapp/cloud backupversion unspecified
  • cpe netapp/clustered data ontapversion unspecified
  • cpe netapp/h300e firmwareversion unspecified
  • cpe netapp/h300s firmwareversion unspecified
  • cpe netapp/h500e firmwareversion unspecified
  • cpe netapp/h500s firmwareversion unspecified
  • cpe netapp/h700s firmwareversion unspecified
  • cpe oracle/mysql serverversion unspecified
  • stated libcurl<= 7.73.0

How to fix CVE-2021-22945

What to do

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

Should you patch?

No confirmed exploitation is on record for CVE-2021-22945. EPSS is 6.68%. Act only if a listed version of the affected product is installed.

Which versions are affected?

Compare what you have installed with 33, 35, <= 7.73.0. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-415: Double Free. EPSS 6.68%. 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.

No public source repository is identified for this product.

Timeline

Detection, updates, and resolution for this record.

  1. Sep 23, 2021 · NIST NVD

    Detected

    When sending data to an MQTT server, libcurl <= 7.73.0 and 7.78.0 could in some circumstances erroneously keep a pointer to an already freed memory area and both use that again in a subsequent call to send data and also free it *again*.

  2. Oct 14, 2026 · NIST NVD

    Updated

    When sending data to an MQTT server, libcurl <= 7.73.0 and 7.78.0 could in some circumstances erroneously keep a pointer to an already freed memory area and both use that again in a subsequent call to send data and also free it *again*.

Sources

  • CVE.orgVulnerability recordCVE-2021-22945

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2021-22945

    30-day exploitation probability 6.7%

    first.org
  • NIST NVDVulnerability recordCVE-2021-22945

    When sending data to an MQTT server, libcurl <= 7.73.0 and 7.78.0 could in some circumstances erroneously keep a pointer to an already freed memory area and both use that again in a subsequent call to send data and also free it *again*.

    nvd.nist.gov

References

Freshness

Last verified in this catalog Oct 16, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.