{
  "cveId": "CVE-2021-3634",
  "url": "https://patchblox.com/security/cve/CVE-2021-3634",
  "summary": "CVE-2021-3634 is fixed in 5 products on 1 platform, first by libssh-4 0.9.3-2ubuntu2.2, released August 25, 2021. It is not reported as exploited. Patch Radar priority: Routine.",
  "title": "libssh: libssh is a library which implements the SSH protocol",
  "description": "libssh is a library which implements the SSH protocol. It can be used to implement client and server applications.\n\nThe following packages have been upgraded to a later upstream version: libssh (0.9.6). (BZ#1896651)\n\nSecurity Fix(es):\n\n* libssh: possible heap-based buffer overflow when rekeying (CVE-2021-3634)\n\nFor more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.\n\nAdditional Changes:\n\nFor detailed information on changes in this release, see the Red Hat Enterprise Linux 8.6 Release Notes linked from the References section.",
  "published": "2021-08-25T17:00:00Z",
  "severity": "Low",
  "cvss": 6.5,
  "cvssVector": "CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:N/A:L",
  "epss": 0.04683,
  "epssPercentile": 0.91836,
  "priority": "Routine",
  "priorityTier": 4,
  "exploited": false,
  "vendorExploited": false,
  "disclosed": false,
  "fixes": [
    {
      "platform": "linux",
      "product": "libssh",
      "release": "RHEL 8",
      "fixedVersion": "0:0.9.6-3.el8",
      "fix": "RHSA-2022:2031",
      "url": "https://patchblox.com/security/fix/linux/rhsa-2022-2031",
      "released": "2022-05-10T00:00:00Z"
    },
    {
      "platform": "linux",
      "product": "libssh",
      "release": "almalinux 8",
      "fixedVersion": "0.9.6-3.el8",
      "fix": "ALSA-2022:2031",
      "url": "https://patchblox.com/security/fix/linux/alsa-2022-2031",
      "released": "2022-05-10T08:14:06Z"
    },
    {
      "platform": "linux",
      "product": "libssh",
      "release": "ol 8",
      "fixedVersion": "0:0.9.6-3.el8",
      "fix": "ELSA-2022-2031",
      "url": "https://patchblox.com/security/fix/linux/elsa-2022-2031",
      "released": "2022-05-17T00:00:00Z"
    },
    {
      "platform": "linux",
      "product": "libssh",
      "release": "rocky 8",
      "fixedVersion": "0:0.9.6-3.el8",
      "fix": "RLSA-2022:2031",
      "url": "https://patchblox.com/security/fix/linux/rlsa-2022-2031",
      "released": "2022-05-10T08:14:06Z"
    },
    {
      "platform": "linux",
      "product": "libssh-4",
      "release": "Ubuntu 20.04 LTS (focal)",
      "fixedVersion": "0.9.3-2ubuntu2.2",
      "fix": "libssh-4 0.9.3-2ubuntu2.2",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-focal-libssh-4-0.9.3-2ubuntu2.2",
      "released": "2021-08-25T17:00:00Z"
    },
    {
      "platform": "linux",
      "product": "libssh-4",
      "release": "Ubuntu 22.04.1 LTS (jammy)",
      "fixedVersion": "0.9.6-1",
      "fix": "libssh-4 0.9.6-1",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-jammy-libssh-4-0.9.6-1",
      "released": "2021-08-25T17:00:00Z"
    },
    {
      "platform": "linux",
      "product": "libssh-config",
      "release": "RHEL 8",
      "fixedVersion": "0:0.9.6-3.el8",
      "fix": "RHSA-2022:2031",
      "url": "https://patchblox.com/security/fix/linux/rhsa-2022-2031",
      "released": "2022-05-10T00:00:00Z"
    },
    {
      "platform": "linux",
      "product": "libssh-config",
      "release": "almalinux 8",
      "fixedVersion": "0.9.6-3.el8",
      "fix": "ALSA-2022:2031",
      "url": "https://patchblox.com/security/fix/linux/alsa-2022-2031",
      "released": "2022-05-10T08:14:06Z"
    },
    {
      "platform": "linux",
      "product": "libssh-config",
      "release": "ol 8",
      "fixedVersion": "0:0.9.6-3.el8",
      "fix": "ELSA-2022-2031",
      "url": "https://patchblox.com/security/fix/linux/elsa-2022-2031",
      "released": "2022-05-17T00:00:00Z"
    },
    {
      "platform": "linux",
      "product": "libssh-devel",
      "release": "RHEL 8",
      "fixedVersion": "0:0.9.6-3.el8",
      "fix": "RHSA-2022:2031",
      "url": "https://patchblox.com/security/fix/linux/rhsa-2022-2031",
      "released": "2022-05-10T00:00:00Z"
    },
    {
      "platform": "linux",
      "product": "libssh-devel",
      "release": "almalinux 8",
      "fixedVersion": "0.9.6-3.el8",
      "fix": "ALSA-2022:2031",
      "url": "https://patchblox.com/security/fix/linux/alsa-2022-2031",
      "released": "2022-05-10T08:14:06Z"
    },
    {
      "platform": "linux",
      "product": "libssh-devel",
      "release": "ol 8",
      "fixedVersion": "0:0.9.6-3.el8",
      "fix": "ELSA-2022-2031",
      "url": "https://patchblox.com/security/fix/linux/elsa-2022-2031",
      "released": "2022-05-17T00:00:00Z"
    },
    {
      "platform": "linux",
      "product": "libssh-gcrypt-4",
      "release": "Ubuntu 20.04 LTS (focal)",
      "fixedVersion": "0.9.3-2ubuntu2.2",
      "fix": "libssh-gcrypt-4 0.9.3-2ubuntu2.2",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-focal-libssh-gcrypt-4-0.9.3-2ubuntu2.2",
      "released": "2021-08-25T17:00:00Z"
    },
    {
      "platform": "linux",
      "product": "libssh-gcrypt-4",
      "release": "Ubuntu 22.04.1 LTS (jammy)",
      "fixedVersion": "0.9.6-1",
      "fix": "libssh-gcrypt-4 0.9.6-1",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-jammy-libssh-gcrypt-4-0.9.6-1",
      "released": "2021-08-25T17:00:00Z"
    }
  ],
  "noFixYet": [],
  "dataAsOf": "2026-11-08T13:06:02Z",
  "attribution": {
    "text": "Data: Patchblox Patch Radar",
    "url": "https://patchblox.com/security/patch-radar",
    "terms": "https://patchblox.com/security/patch-radar/use-the-data"
  }
}