GCVE Workshop - 22 September 2026 (14:00-18:00), Luxembourg Before The Vulnopticon Conference - Registration

CVE-2021-44732 (GCVE-0-2021-44732)

Vulnerability from cvelistv5 – Published: 2021-12-20 00:00 – Updated: 2025-11-03 19:26
VLAI
Summary
Mbed TLS before 3.0.1 has a double free in certain out-of-memory conditions, as demonstrated by an mbedtls_ssl_set_session() failure.
Severity
9.8 (Critical)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CWE
  • n/a
Assigner
References
Show details on NVD website
To clipboard 

{
  "containers": {
    "adp": [
      {
        "providerMetadata": {
          "dateUpdated": "2025-11-03T19:26:32.887Z",
          "orgId": "af854a3a-2127-422b-91ae-364da2661108",
          "shortName": "CVE"
        },
        "references": [
          {
            "tags": [
              "x_transferred"
            ],
            "url": "https://github.com/ARMmbed/mbedtls/releases"
          },
          {
            "tags": [
              "x_transferred"
            ],
            "url": "https://tls.mbed.org/tech-updates/security-advisories/mbedtls-security-advisory-2021-12"
          },
          {
            "tags": [
              "x_transferred"
            ],
            "url": "https://bugs.gentoo.org/829660"
          },
          {
            "tags": [
              "x_transferred"
            ],
            "url": "https://github.com/ARMmbed/mbedtls/releases/tag/v2.16.12"
          },
          {
            "tags": [
              "x_transferred"
            ],
            "url": "https://github.com/ARMmbed/mbedtls/releases/tag/v2.28.0"
          },
          {
            "tags": [
              "x_transferred"
            ],
            "url": "https://github.com/ARMmbed/mbedtls/releases/tag/v3.1.0"
          },
          {
            "name": "[debian-lts-announce] 20221225 [SECURITY] [DLA 3249-1] mbedtls security update",
            "tags": [
              "mailing-list",
              "x_transferred"
            ],
            "url": "https://lists.debian.org/debian-lts-announce/2022/12/msg00036.html"
          },
          {
            "url": "https://lists.debian.org/debian-lts-announce/2025/06/msg00034.html"
          }
        ],
        "title": "CVE Program Container"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "n/a",
          "vendor": "n/a",
          "versions": [
            {
              "status": "affected",
              "version": "n/a"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "Mbed TLS before 3.0.1 has a double free in certain out-of-memory conditions, as demonstrated by an mbedtls_ssl_set_session() failure."
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "description": "n/a",
              "lang": "en",
              "type": "text"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2022-12-26T00:00:00.000Z",
        "orgId": "8254265b-2729-46b6-b9e3-3dfca2d5bfca",
        "shortName": "mitre"
      },
      "references": [
        {
          "url": "https://github.com/ARMmbed/mbedtls/releases"
        },
        {
          "url": "https://tls.mbed.org/tech-updates/security-advisories/mbedtls-security-advisory-2021-12"
        },
        {
          "url": "https://bugs.gentoo.org/829660"
        },
        {
          "url": "https://github.com/ARMmbed/mbedtls/releases/tag/v2.16.12"
        },
        {
          "url": "https://github.com/ARMmbed/mbedtls/releases/tag/v2.28.0"
        },
        {
          "url": "https://github.com/ARMmbed/mbedtls/releases/tag/v3.1.0"
        },
        {
          "name": "[debian-lts-announce] 20221225 [SECURITY] [DLA 3249-1] mbedtls security update",
          "tags": [
            "mailing-list"
          ],
          "url": "https://lists.debian.org/debian-lts-announce/2022/12/msg00036.html"
        }
      ]
    }
  },
  "cveMetadata": {
    "assignerOrgId": "8254265b-2729-46b6-b9e3-3dfca2d5bfca",
    "assignerShortName": "mitre",
    "cveId": "CVE-2021-44732",
    "datePublished": "2021-12-20T00:00:00.000Z",
    "dateReserved": "2021-12-08T00:00:00.000Z",
    "dateUpdated": "2025-11-03T19:26:32.887Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2021-44732",
      "date": "2026-09-19",
      "epss": "0.02577",
      "percentile": "0.84503"
    },
    "fkie_nvd": {
      "configurations": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:a:arm:mbed_tls:*:*:*:*:*:*:*:*",
                  "matchCriteriaId": "BC31D4CC-3B31-436A-8702-9FEC260E0718",
                  "versionEndExcluding": "2.16.12",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:a:arm:mbed_tls:*:*:*:*:*:*:*:*",
                  "matchCriteriaId": "F65087D6-7AFE-4E43-AD74-C1B200CF7101",
                  "versionEndExcluding": "2.28.0",
                  "versionStartIncluding": "2.17.0",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:a:arm:mbed_tls:3.0.0:-:*:*:*:*:*:*",
                  "matchCriteriaId": "4D17176C-2FEA-4463-AC8A-14D762D24D15",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:a:arm:mbed_tls:3.0.0:preview1:*:*:*:*:*:*",
                  "matchCriteriaId": "AE299F79-D7BF-4668-91B0-B50C194C5FBF",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        },
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*",
                  "matchCriteriaId": "07B237A9-69A3-4A9C-9DA0-4E06BD37AE73",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "Mbed TLS before 3.0.1 has a double free in certain out-of-memory conditions, as demonstrated by an mbedtls_ssl_set_session() failure."
        },
        {
          "lang": "es",
          "value": "Mbed TLS versiones anteriores a 3.0.1,presenta una doble liberaci\u00f3n en determinadas condiciones de salida de memoria, como es demostrado por un fallo de la funci\u00f3n mbedtls_ssl_set_session()"
        }
      ],
      "id": "CVE-2021-44732",
      "lastModified": "2024-11-21T06:31:28.383",
      "metrics": {
        "cvssMetricV2": [
          {
            "acInsufInfo": false,
            "baseSeverity": "HIGH",
            "cvssData": {
              "accessComplexity": "LOW",
              "accessVector": "NETWORK",
              "authentication": "NONE",
              "availabilityImpact": "PARTIAL",
              "baseScore": 7.5,
              "confidentialityImpact": "PARTIAL",
              "integrityImpact": "PARTIAL",
              "vectorString": "AV:N/AC:L/Au:N/C:P/I:P/A:P",
              "version": "2.0"
            },
            "exploitabilityScore": 10.0,
            "impactScore": 6.4,
            "obtainAllPrivilege": false,
            "obtainOtherPrivilege": false,
            "obtainUserPrivilege": false,
            "source": "nvd@nist.gov",
            "type": "Primary",
            "userInteractionRequired": false
          }
        ],
        "cvssMetricV31": [
          {
            "cvssData": {
              "attackComplexity": "LOW",
              "attackVector": "NETWORK",
              "availabilityImpact": "HIGH",
              "baseScore": 9.8,
              "baseSeverity": "CRITICAL",
              "confidentialityImpact": "HIGH",
              "integrityImpact": "HIGH",
              "privilegesRequired": "NONE",
              "scope": "UNCHANGED",
              "userInteraction": "NONE",
              "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
              "version": "3.1"
            },
            "exploitabilityScore": 3.9,
            "impactScore": 5.9,
            "source": "nvd@nist.gov",
            "type": "Primary"
          }
        ]
      },
      "published": "2021-12-20T08:15:06.620",
      "references": [
        {
          "source": "cve@mitre.org",
          "tags": [
            "Issue Tracking",
            "Mailing List",
            "Third Party Advisory"
          ],
          "url": "https://bugs.gentoo.org/829660"
        },
        {
          "source": "cve@mitre.org",
          "tags": [
            "Release Notes"
          ],
          "url": "https://github.com/ARMmbed/mbedtls/releases"
        },
        {
          "source": "cve@mitre.org",
          "tags": [
            "Release Notes"
          ],
          "url": "https://github.com/ARMmbed/mbedtls/releases/tag/v2.16.12"
        },
        {
          "source": "cve@mitre.org",
          "tags": [
            "Release Notes"
          ],
          "url": "https://github.com/ARMmbed/mbedtls/releases/tag/v2.28.0"
        },
        {
          "source": "cve@mitre.org",
          "tags": [
            "Release Notes"
          ],
          "url": "https://github.com/ARMmbed/mbedtls/releases/tag/v3.1.0"
        },
        {
          "source": "cve@mitre.org",
          "tags": [
            "Mailing List",
            "Third Party Advisory"
          ],
          "url": "https://lists.debian.org/debian-lts-announce/2022/12/msg00036.html"
        },
        {
          "source": "cve@mitre.org",
          "tags": [
            "Exploit",
            "Mitigation",
            "Third Party Advisory"
          ],
          "url": "https://tls.mbed.org/tech-updates/security-advisories/mbedtls-security-advisory-2021-12"
        },
        {
          "source": "af854a3a-2127-422b-91ae-364da2661108",
          "tags": [
            "Issue Tracking",
            "Mailing List",
            "Third Party Advisory"
          ],
          "url": "https://bugs.gentoo.org/829660"
        },
        {
          "source": "af854a3a-2127-422b-91ae-364da2661108",
          "tags": [
            "Release Notes"
          ],
          "url": "https://github.com/ARMmbed/mbedtls/releases"
        },
        {
          "source": "af854a3a-2127-422b-91ae-364da2661108",
          "tags": [
            "Release Notes"
          ],
          "url": "https://github.com/ARMmbed/mbedtls/releases/tag/v2.16.12"
        },
        {
          "source": "af854a3a-2127-422b-91ae-364da2661108",
          "tags": [
            "Release Notes"
          ],
          "url": "https://github.com/ARMmbed/mbedtls/releases/tag/v2.28.0"
        },
        {
          "source": "af854a3a-2127-422b-91ae-364da2661108",
          "tags": [
            "Release Notes"
          ],
          "url": "https://github.com/ARMmbed/mbedtls/releases/tag/v3.1.0"
        },
        {
          "source": "af854a3a-2127-422b-91ae-364da2661108",
          "tags": [
            "Mailing List",
            "Third Party Advisory"
          ],
          "url": "https://lists.debian.org/debian-lts-announce/2022/12/msg00036.html"
        },
        {
          "source": "af854a3a-2127-422b-91ae-364da2661108",
          "tags": [
            "Exploit",
            "Mitigation",
            "Third Party Advisory"
          ],
          "url": "https://tls.mbed.org/tech-updates/security-advisories/mbedtls-security-advisory-2021-12"
        }
      ],
      "sourceIdentifier": "cve@mitre.org",
      "vulnStatus": "Modified",
      "weaknesses": [
        {
          "description": [
            {
              "lang": "en",
              "value": "CWE-415"
            }
          ],
          "source": "nvd@nist.gov",
          "type": "Primary"
        }
      ]
    },
    "microsoft_vex": {
      "current_release_date": "2026-02-18T02:45:56.000Z",
      "cve": "CVE-2021-44732",
      "id": "msrc_CVE-2021-44732",
      "initial_release_date": "2021-12-02T00:00:00.000Z",
      "product_status:known_not_affected": "3",
      "source": "Microsoft CSAF VEX",
      "status": "final",
      "title": "Mbed TLS before 3.0.1 has a double free in certain out-of-memory conditions, as demonstrated by an mbedtls_ssl_set_session() failure.",
      "url": "https://msrc.microsoft.com/csaf/vex/2021/msrc_cve-2021-44732.json",
      "version": "2"
    },
    "nvd": {
      "cve": {
        "affected": [
          {
            "affectedData": [
              {
                "product": "n/a",
                "vendor": "n/a",
                "versions": [
                  {
                    "status": "affected",
                    "version": "n/a"
                  }
                ]
              }
            ],
            "source": "cve@mitre.org"
          }
        ],
        "configurations": [
          {
            "nodes": [
              {
                "cpeMatch": [
                  {
                    "criteria": "cpe:2.3:a:arm:mbed_tls:*:*:*:*:*:*:*:*",
                    "matchCriteriaId": "BC31D4CC-3B31-436A-8702-9FEC260E0718",
                    "versionEndExcluding": "2.16.12",
                    "vulnerable": true
                  },
                  {
                    "criteria": "cpe:2.3:a:arm:mbed_tls:*:*:*:*:*:*:*:*",
                    "matchCriteriaId": "F65087D6-7AFE-4E43-AD74-C1B200CF7101",
                    "versionEndExcluding": "2.28.0",
                    "versionStartIncluding": "2.17.0",
                    "vulnerable": true
                  },
                  {
                    "criteria": "cpe:2.3:a:trustedfirmware:mbed_tls:3.0.0:-:*:*:*:*:*:*",
                    "matchCriteriaId": "38E3FA71-63D6-43EE-8A2D-4EEEE652B98F",
                    "vulnerable": true
                  },
                  {
                    "criteria": "cpe:2.3:a:trustedfirmware:mbed_tls:3.0.0:preview1:*:*:*:*:*:*",
                    "matchCriteriaId": "CCE50A73-640F-4088-A6A1-95FA55FFE621",
                    "vulnerable": true
                  }
                ],
                "negate": false,
                "operator": "OR"
              }
            ]
          },
          {
            "nodes": [
              {
                "cpeMatch": [
                  {
                    "criteria": "cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*",
                    "matchCriteriaId": "07B237A9-69A3-4A9C-9DA0-4E06BD37AE73",
                    "vulnerable": true
                  }
                ],
                "negate": false,
                "operator": "OR"
              }
            ]
          }
        ],
        "cveTags": [],
        "descriptions": [
          {
            "lang": "en",
            "value": "Mbed TLS before 3.0.1 has a double free in certain out-of-memory conditions, as demonstrated by an mbedtls_ssl_set_session() failure."
          },
          {
            "lang": "es",
            "value": "Mbed TLS versiones anteriores a 3.0.1,presenta una doble liberaci\u00f3n en determinadas condiciones de salida de memoria, como es demostrado por un fallo de la funci\u00f3n mbedtls_ssl_set_session()"
          }
        ],
        "id": "CVE-2021-44732",
        "lastModified": "2026-06-17T04:12:46.600",
        "metrics": {
          "cvssMetricV2": [
            {
              "acInsufInfo": false,
              "baseSeverity": "HIGH",
              "cvssData": {
                "accessComplexity": "LOW",
                "accessVector": "NETWORK",
                "authentication": "NONE",
                "availabilityImpact": "PARTIAL",
                "baseScore": 7.5,
                "confidentialityImpact": "PARTIAL",
                "integrityImpact": "PARTIAL",
                "vectorString": "AV:N/AC:L/Au:N/C:P/I:P/A:P",
                "version": "2.0"
              },
              "exploitabilityScore": 10.0,
              "impactScore": 6.4,
              "obtainAllPrivilege": false,
              "obtainOtherPrivilege": false,
              "obtainUserPrivilege": false,
              "source": "nvd@nist.gov",
              "type": "Primary",
              "userInteractionRequired": false
            }
          ],
          "cvssMetricV31": [
            {
              "cvssData": {
                "attackComplexity": "LOW",
                "attackVector": "NETWORK",
                "availabilityImpact": "HIGH",
                "baseScore": 9.8,
                "baseSeverity": "CRITICAL",
                "confidentialityImpact": "HIGH",
                "integrityImpact": "HIGH",
                "privilegesRequired": "NONE",
                "scope": "UNCHANGED",
                "userInteraction": "NONE",
                "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
                "version": "3.1"
              },
              "exploitabilityScore": 3.9,
              "impactScore": 5.9,
              "source": "nvd@nist.gov",
              "type": "Primary"
            }
          ]
        },
        "published": "2021-12-20T08:15:06.620",
        "references": [
          {
            "source": "cve@mitre.org",
            "tags": [
              "Issue Tracking",
              "Mailing List",
              "Third Party Advisory"
            ],
            "url": "https://bugs.gentoo.org/829660"
          },
          {
            "source": "cve@mitre.org",
            "tags": [
              "Release Notes"
            ],
            "url": "https://github.com/ARMmbed/mbedtls/releases"
          },
          {
            "source": "cve@mitre.org",
            "tags": [
              "Release Notes"
            ],
            "url": "https://github.com/ARMmbed/mbedtls/releases/tag/v2.16.12"
          },
          {
            "source": "cve@mitre.org",
            "tags": [
              "Release Notes"
            ],
            "url": "https://github.com/ARMmbed/mbedtls/releases/tag/v2.28.0"
          },
          {
            "source": "cve@mitre.org",
            "tags": [
              "Release Notes"
            ],
            "url": "https://github.com/ARMmbed/mbedtls/releases/tag/v3.1.0"
          },
          {
            "source": "cve@mitre.org",
            "tags": [
              "Mailing List",
              "Third Party Advisory"
            ],
            "url": "https://lists.debian.org/debian-lts-announce/2022/12/msg00036.html"
          },
          {
            "source": "cve@mitre.org",
            "tags": [
              "Exploit",
              "Mitigation",
              "Third Party Advisory"
            ],
            "url": "https://tls.mbed.org/tech-updates/security-advisories/mbedtls-security-advisory-2021-12"
          },
          {
            "source": "af854a3a-2127-422b-91ae-364da2661108",
            "tags": [
              "Issue Tracking",
              "Mailing List",
              "Third Party Advisory"
            ],
            "url": "https://bugs.gentoo.org/829660"
          },
          {
            "source": "af854a3a-2127-422b-91ae-364da2661108",
            "tags": [
              "Release Notes"
            ],
            "url": "https://github.com/ARMmbed/mbedtls/releases"
          },
          {
            "source": "af854a3a-2127-422b-91ae-364da2661108",
            "tags": [
              "Release Notes"
            ],
            "url": "https://github.com/ARMmbed/mbedtls/releases/tag/v2.16.12"
          },
          {
            "source": "af854a3a-2127-422b-91ae-364da2661108",
            "tags": [
              "Release Notes"
            ],
            "url": "https://github.com/ARMmbed/mbedtls/releases/tag/v2.28.0"
          },
          {
            "source": "af854a3a-2127-422b-91ae-364da2661108",
            "tags": [
              "Release Notes"
            ],
            "url": "https://github.com/ARMmbed/mbedtls/releases/tag/v3.1.0"
          },
          {
            "source": "af854a3a-2127-422b-91ae-364da2661108",
            "tags": [
              "Mailing List",
              "Third Party Advisory"
            ],
            "url": "https://lists.debian.org/debian-lts-announce/2022/12/msg00036.html"
          },
          {
            "source": "af854a3a-2127-422b-91ae-364da2661108",
            "url": "https://lists.debian.org/debian-lts-announce/2025/06/msg00034.html"
          },
          {
            "source": "af854a3a-2127-422b-91ae-364da2661108",
            "tags": [
              "Exploit",
              "Mitigation",
              "Third Party Advisory"
            ],
            "url": "https://tls.mbed.org/tech-updates/security-advisories/mbedtls-security-advisory-2021-12"
          }
        ],
        "sourceIdentifier": "cve@mitre.org",
        "vulnStatus": "Modified",
        "weaknesses": [
          {
            "description": [
              {
                "lang": "en",
                "value": "CWE-415"
              }
            ],
            "source": "nvd@nist.gov",
            "type": "Primary"
          }
        ]
      }
    },
    "redhat_vex": {
      "current_release_date": "2025-11-21T10:24:32+00:00",
      "cve": "CVE-2021-44732",
      "id": "CVE-2021-44732",
      "initial_release_date": "2021-12-19T00:00:00+00:00",
      "product_status:known_not_affected": "1",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "mbedtls: potential double-free after an out of memory error",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2021/cve-2021-44732.json",
      "version": "3"
    },
    "suse_vex": {
      "aggregate_severity": "critical",
      "current_release_date": "2025-02-17T05:04:38Z",
      "cve": "CVE-2021-44732",
      "id": "CVE-2021-44732",
      "initial_release_date": "2023-02-15T03:36:31Z",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2021-44732",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2021-44732.json",
      "version": "5"
    }
  }
}



Log in or create an account to share your comment.




Tags
Taxonomy of the tags.





Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


Detection rules are retrieved from Rulezet.


Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.