{
  "cveId": "CVE-2021-23840",
  "url": "https://patchblox.com/security/cve/CVE-2021-23840",
  "summary": "CVE-2021-23840 is fixed in 16 products on 1 platform, first by libssl1.0.0 1.0.2n-1ubuntu5.6, released February 16, 2021. It is not reported as exploited. Patch Radar priority: High.",
  "title": "libssl3t64: Calls to EVP_CipherUpdate, EVP_EncryptUpdate and EVP_DecryptUpdate mayoverflow the output length argument in some cas...",
  "description": "Calls to EVP_CipherUpdate, EVP_EncryptUpdate and EVP_DecryptUpdate mayoverflow the output length argument in some cases where the input length isclose to the maximum permissable length for an integer on the platform. Insuch cases the return value from the function call will be 1 (indicatingsuccess), but the output length value will be negative. This could causeapplications to behave incorrectly or crash. OpenSSL versions 1.1.1i andbelow are affected by this issue. Users of these versions should upgrade toOpenSSL 1.1.1j. OpenSSL versions 1.0.2x and below are affected by thisissue. However OpenSSL 1.0.2 is out of support and no longer receivingpublic updates. Premium support customers of OpenSSL 1.0.2 should upgradeto 1.0.2y. Other users should upgrade to 1.1.1j. Fixed in OpenSSL 1.1.1j(Affected 1.1.1-1.1.1i). Fixed in OpenSSL 1.0.2y (Affected 1.0.2-1.0.2x).",
  "published": "2021-02-16T09:15:00Z",
  "severity": "Low",
  "cvss": 7.5,
  "epss": 0.50732,
  "epssPercentile": 0.9893,
  "priority": "High",
  "priorityTier": 3,
  "exploited": false,
  "vendorExploited": false,
  "disclosed": false,
  "fixes": [
    {
      "platform": "linux",
      "product": "edk2-aarch64",
      "release": "RHEL 8",
      "fixedVersion": "0:20210527gite1999b264f1f-3.el8",
      "fix": "RHSA-2021:4198",
      "url": "https://patchblox.com/security/fix/linux/rhsa-2021-4198",
      "released": "2021-11-09T00:00:00Z"
    },
    {
      "platform": "linux",
      "product": "edk2-ovmf",
      "release": "RHEL 8",
      "fixedVersion": "0:20210527gite1999b264f1f-3.el8",
      "fix": "RHSA-2021:4198",
      "url": "https://patchblox.com/security/fix/linux/rhsa-2021-4198",
      "released": "2021-11-09T00:00:00Z"
    },
    {
      "platform": "linux",
      "product": "libssl1.0.0",
      "release": "Ubuntu 18.04.6 LTS (bionic)",
      "fixedVersion": "1.0.2n-1ubuntu5.6",
      "fix": "libssl1.0.0 1.0.2n-1ubuntu5.6",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-bionic-libssl1.0.0-1.0.2n-1ubuntu5.6",
      "released": "2021-02-16T09:15:00Z"
    },
    {
      "platform": "linux",
      "product": "libssl1.1",
      "release": "Ubuntu 18.04.6 LTS (bionic)",
      "fixedVersion": "1.1.1-1ubuntu2.1~18.04.8",
      "fix": "libssl1.1 1.1.1-1ubuntu2.1~18.04.8",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-bionic-libssl1.1-1.1.1-1ubuntu2.1-18.04.8",
      "released": "2021-02-16T09:15:00Z"
    },
    {
      "platform": "linux",
      "product": "libssl1.1",
      "release": "Ubuntu 20.04 LTS (focal)",
      "fixedVersion": "1.1.1f-1ubuntu2.2",
      "fix": "libssl1.1 1.1.1f-1ubuntu2.2",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-focal-libssl1.1-1.1.1f-1ubuntu2.2",
      "released": "2021-02-16T09:15:00Z"
    },
    {
      "platform": "linux",
      "product": "libssl3t64",
      "release": "Ubuntu 24.10 (oracular)",
      "fixedVersion": "1.1.1j-1ubuntu1",
      "fix": "libssl3t64 1.1.1j-1ubuntu1",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-oracular-libssl3t64-1.1.1j-1ubuntu1",
      "released": "2026-01-16T01:42:22Z"
    },
    {
      "platform": "linux",
      "product": "libssl3t64",
      "release": "Ubuntu 25.04 (plucky)",
      "fixedVersion": "1.1.1j-1ubuntu1",
      "fix": "libssl3t64 1.1.1j-1ubuntu1",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-plucky-libssl3t64-1.1.1j-1ubuntu1",
      "released": "2026-01-16T01:42:24Z"
    },
    {
      "platform": "linux",
      "product": "openssl",
      "release": "RHEL 8",
      "fixedVersion": "1:1.1.1k-4.el8",
      "fix": "RHSA-2021:4424",
      "url": "https://patchblox.com/security/fix/linux/rhsa-2021-4424",
      "released": "2021-11-09T00:00:00Z"
    },
    {
      "platform": "linux",
      "product": "openssl",
      "release": "Ubuntu 18.04.6 LTS (bionic)",
      "fixedVersion": "1.1.1-1ubuntu2.1~18.04.8",
      "fix": "openssl 1.1.1-1ubuntu2.1~18.04.8",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-bionic-openssl-1.1.1-1ubuntu2.1-18.04.8",
      "released": "2021-02-16T09:15:00Z"
    },
    {
      "platform": "linux",
      "product": "openssl",
      "release": "Ubuntu 20.04 LTS (focal)",
      "fixedVersion": "1.1.1f-1ubuntu2.2",
      "fix": "openssl 1.1.1f-1ubuntu2.2",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-focal-openssl-1.1.1f-1ubuntu2.2",
      "released": "2021-02-16T09:15:00Z"
    },
    {
      "platform": "linux",
      "product": "openssl",
      "release": "Ubuntu 24.10 (oracular)",
      "fixedVersion": "1.1.1j-1ubuntu1",
      "fix": "openssl 1.1.1j-1ubuntu1",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-oracular-openssl-1.1.1j-1ubuntu1",
      "released": "2026-01-16T01:42:22Z"
    },
    {
      "platform": "linux",
      "product": "openssl",
      "release": "Ubuntu 25.04 (plucky)",
      "fixedVersion": "1.1.1j-1ubuntu1",
      "fix": "openssl 1.1.1j-1ubuntu1",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-plucky-openssl-1.1.1j-1ubuntu1",
      "released": "2026-01-16T01:42:24Z"
    },
    {
      "platform": "linux",
      "product": "openssl",
      "release": "ol 8",
      "fixedVersion": "2:1.1.1k-4.ksplice1.el8",
      "fix": "ELSA-2021-9561",
      "url": "https://patchblox.com/security/fix/linux/elsa-2021-9561",
      "released": "2021-11-23T00:00:00Z"
    },
    {
      "platform": "linux",
      "product": "openssl-debugsource",
      "release": "ol 8",
      "fixedVersion": "2:1.1.1k-4.ksplice1.el8",
      "fix": "ELSA-2021-9561",
      "url": "https://patchblox.com/security/fix/linux/elsa-2021-9561",
      "released": "2021-11-23T00:00:00Z"
    },
    {
      "platform": "linux",
      "product": "openssl-devel",
      "release": "RHEL 8",
      "fixedVersion": "1:1.1.1k-4.el8",
      "fix": "RHSA-2021:4424",
      "url": "https://patchblox.com/security/fix/linux/rhsa-2021-4424",
      "released": "2021-11-09T00:00:00Z"
    },
    {
      "platform": "linux",
      "product": "openssl-devel",
      "release": "ol 8",
      "fixedVersion": "2:1.1.1k-4.ksplice1.el8",
      "fix": "ELSA-2021-9561",
      "url": "https://patchblox.com/security/fix/linux/elsa-2021-9561",
      "released": "2021-11-23T00:00:00Z"
    },
    {
      "platform": "linux",
      "product": "openssl-libs",
      "release": "RHEL 8",
      "fixedVersion": "1:1.1.1k-4.el8",
      "fix": "RHSA-2021:4424",
      "url": "https://patchblox.com/security/fix/linux/rhsa-2021-4424",
      "released": "2021-11-09T00:00:00Z"
    },
    {
      "platform": "linux",
      "product": "openssl-libs",
      "release": "ol 8",
      "fixedVersion": "2:1.1.1k-4.ksplice1.el8",
      "fix": "ELSA-2021-9561",
      "url": "https://patchblox.com/security/fix/linux/elsa-2021-9561",
      "released": "2021-11-23T00:00:00Z"
    },
    {
      "platform": "linux",
      "product": "openssl-perl",
      "release": "RHEL 8",
      "fixedVersion": "1:1.1.1k-4.el8",
      "fix": "RHSA-2021:4424",
      "url": "https://patchblox.com/security/fix/linux/rhsa-2021-4424",
      "released": "2021-11-09T00:00:00Z"
    },
    {
      "platform": "linux",
      "product": "openssl-perl",
      "release": "ol 8",
      "fixedVersion": "2:1.1.1k-4.ksplice1.el8",
      "fix": "ELSA-2021-9561",
      "url": "https://patchblox.com/security/fix/linux/elsa-2021-9561",
      "released": "2021-11-23T00:00:00Z"
    },
    {
      "platform": "linux",
      "product": "openssl-static",
      "release": "ol 8",
      "fixedVersion": "2:1.1.1k-4.ksplice1.el8",
      "fix": "ELSA-2021-9561",
      "url": "https://patchblox.com/security/fix/linux/elsa-2021-9561",
      "released": "2021-11-23T00:00:00Z"
    },
    {
      "platform": "linux",
      "product": "openssl1.0",
      "release": "Ubuntu 18.04.6 LTS (bionic)",
      "fixedVersion": "1.0.2n-1ubuntu5.6",
      "fix": "openssl1.0 1.0.2n-1ubuntu5.6",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-bionic-openssl1.0-1.0.2n-1ubuntu5.6",
      "released": "2021-02-16T09:15:00Z"
    },
    {
      "platform": "linux",
      "product": "ovmf",
      "release": "Ubuntu 20.04 LTS (focal)",
      "fixedVersion": "0~20191122.bd85bf54-2ubuntu3.3",
      "fix": "ovmf 0~20191122.bd85bf54-2ubuntu3.3",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-focal-ovmf-0-20191122.bd85bf54-2ubuntu3.3",
      "released": "2021-09-13T17:00:00Z"
    },
    {
      "platform": "linux",
      "product": "qemu-efi",
      "release": "Ubuntu 20.04 LTS (focal)",
      "fixedVersion": "0~20191122.bd85bf54-2ubuntu3.3",
      "fix": "qemu-efi 0~20191122.bd85bf54-2ubuntu3.3",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-focal-qemu-efi-0-20191122.bd85bf54-2ubuntu3.3",
      "released": "2021-09-13T17:00:00Z"
    },
    {
      "platform": "linux",
      "product": "qemu-efi-aarch64",
      "release": "Ubuntu 20.04 LTS (focal)",
      "fixedVersion": "0~20191122.bd85bf54-2ubuntu3.3",
      "fix": "qemu-efi-aarch64 0~20191122.bd85bf54-2ubuntu3.3",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-focal-qemu-efi-aarch64-0-20191122.bd85bf54-2ubuntu3.3",
      "released": "2021-09-13T17:00:00Z"
    },
    {
      "platform": "linux",
      "product": "qemu-efi-arm",
      "release": "Ubuntu 20.04 LTS (focal)",
      "fixedVersion": "0~20191122.bd85bf54-2ubuntu3.3",
      "fix": "qemu-efi-arm 0~20191122.bd85bf54-2ubuntu3.3",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-focal-qemu-efi-arm-0-20191122.bd85bf54-2ubuntu3.3",
      "released": "2021-09-13T17:00:00Z"
    }
  ],
  "noFixYet": [],
  "dataAsOf": "2026-11-10T13:56:55Z",
  "attribution": {
    "text": "Data: Patchblox Patch Radar",
    "url": "https://patchblox.com/security/patch-radar",
    "terms": "https://patchblox.com/security/patch-radar/use-the-data"
  }
}