{
  "cveId": "CVE-2021-36740",
  "url": "https://patchblox.com/security/cve/CVE-2021-36740",
  "summary": "CVE-2021-36740 is fixed in 5 products on 1 platform, first by RHSA-2021:2988, released August 2, 2021. It is not reported as exploited. Patch Radar priority: High.",
  "title": "varnish: Varnish Cache is a high-performance HTTP accelerator",
  "description": "Varnish Cache is a high-performance HTTP accelerator. It stores web pages in memory so web servers don\u0027t have to create the same web page over and over again, giving the website a significant speed up.\n\nSecurity Fix(es):\n\n* varnish: HTTP/2 request smuggling attack via a large Content-Length header for a POST request (CVE-2021-36740)\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.",
  "published": "2021-07-14T10:15:00Z",
  "severity": "Important",
  "cvss": 8.1,
  "epss": 0.01599,
  "epssPercentile": 0.75925,
  "priority": "High",
  "priorityTier": 3,
  "exploited": false,
  "vendorExploited": false,
  "disclosed": false,
  "fixes": [
    {
      "platform": "linux",
      "product": "libvarnishapi2",
      "release": "Ubuntu 20.04 LTS (focal)",
      "fixedVersion": "6.2.1-2ubuntu0.1",
      "fix": "libvarnishapi2 6.2.1-2ubuntu0.1",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-focal-libvarnishapi2-6.2.1-2ubuntu0.1",
      "released": "2022-01-25T17:15:00Z"
    },
    {
      "platform": "linux",
      "product": "varnish",
      "release": "Debian 11.6 (bullseye)",
      "fixedVersion": "6.5.1-1\u002Bdeb11u2",
      "fix": "DSA-5088-1",
      "url": "https://patchblox.com/security/fix/linux/dsa-5088-1",
      "released": "2022-03-03T00:00:00Z"
    },
    {
      "platform": "linux",
      "product": "varnish",
      "release": "RHEL 8",
      "fixedVersion": "0:6.0.6-2.module\u002Bel8.4.0\u002B11921\u002B1a6539fc.1",
      "fix": "RHSA-2021:2988",
      "url": "https://patchblox.com/security/fix/linux/rhsa-2021-2988",
      "released": "2021-08-02T00:00:00Z"
    },
    {
      "platform": "linux",
      "product": "varnish",
      "release": "Ubuntu 20.04 LTS (focal)",
      "fixedVersion": "6.2.1-2ubuntu0.1",
      "fix": "varnish 6.2.1-2ubuntu0.1",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-focal-varnish-6.2.1-2ubuntu0.1",
      "released": "2022-01-25T17:15:00Z"
    },
    {
      "platform": "linux",
      "product": "varnish",
      "release": "ol 8",
      "fixedVersion": "0:6.0.6-2.module\u002Bel8.4.0\u002B20258\u002Bf99218b2.1",
      "fix": "ELSA-2021-2988",
      "url": "https://patchblox.com/security/fix/linux/elsa-2021-2988",
      "released": "2021-08-03T00:00:00Z"
    },
    {
      "platform": "linux",
      "product": "varnish-devel",
      "release": "RHEL 8",
      "fixedVersion": "0:6.0.6-2.module\u002Bel8.4.0\u002B11921\u002B1a6539fc.1",
      "fix": "RHSA-2021:2988",
      "url": "https://patchblox.com/security/fix/linux/rhsa-2021-2988",
      "released": "2021-08-02T00:00:00Z"
    },
    {
      "platform": "linux",
      "product": "varnish-devel",
      "release": "ol 8",
      "fixedVersion": "0:6.0.6-2.module\u002Bel8.4.0\u002B20258\u002Bf99218b2.1",
      "fix": "ELSA-2021-2988",
      "url": "https://patchblox.com/security/fix/linux/elsa-2021-2988",
      "released": "2021-08-03T00:00:00Z"
    },
    {
      "platform": "linux",
      "product": "varnish-docs",
      "release": "RHEL 8",
      "fixedVersion": "0:6.0.6-2.module\u002Bel8.4.0\u002B11921\u002B1a6539fc.1",
      "fix": "RHSA-2021:2988",
      "url": "https://patchblox.com/security/fix/linux/rhsa-2021-2988",
      "released": "2021-08-02T00:00:00Z"
    },
    {
      "platform": "linux",
      "product": "varnish-docs",
      "release": "ol 8",
      "fixedVersion": "0:6.0.6-2.module\u002Bel8.4.0\u002B20258\u002Bf99218b2.1",
      "fix": "ELSA-2021-2988",
      "url": "https://patchblox.com/security/fix/linux/elsa-2021-2988",
      "released": "2021-08-03T00:00:00Z"
    },
    {
      "platform": "linux",
      "product": "varnish-modules",
      "release": "RHEL 8",
      "fixedVersion": "0:0.15.0-5.module\u002Bel8.3.0\u002B6843\u002Bb3b42fcc",
      "fix": "RHSA-2021:2988",
      "url": "https://patchblox.com/security/fix/linux/rhsa-2021-2988",
      "released": "2021-08-02T00:00:00Z"
    },
    {
      "platform": "linux",
      "product": "varnish-modules",
      "release": "ol 8",
      "fixedVersion": "0:0.15.0-5.module\u002Bel8.3.0\u002B7653\u002B45014445",
      "fix": "ELSA-2021-2988",
      "url": "https://patchblox.com/security/fix/linux/elsa-2021-2988",
      "released": "2021-08-03T00:00:00Z"
    }
  ],
  "noFixYet": [],
  "dataAsOf": "2026-11-08T00:53:09Z",
  "attribution": {
    "text": "Data: Patchblox Patch Radar",
    "url": "https://patchblox.com/security/patch-radar",
    "terms": "https://patchblox.com/security/patch-radar/use-the-data"
  }
}