{
  "threat_severity" : "Moderate",
  "public_date" : "2026-04-12T19:23:03Z",
  "bugzilla" : {
    "description" : "varnish: Varnish Cache: Denial of Service via workspace overflow during HTTP/1 pipelining",
    "id" : "2457697",
    "url" : "https://bugzilla.redhat.com/show_bug.cgi?id=2457697"
  },
  "cvss3" : {
    "cvss3_base_score" : "5.9",
    "cvss3_scoring_vector" : "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H",
    "status" : "draft"
  },
  "cwe" : "CWE-131",
  "details" : [ "A flaw was found in Varnish Cache. A malicious client can exploit a 'workspace overflow' vulnerability by sending an HTTP/1 request, waiting for the session to release its worker thread, and then resuming traffic with multiple requests to trigger a pipelining operation. This can lead to a workspace overflow, causing the Varnish server to panic and crash, resulting in a Denial of Service (DoS)." ],
  "package_state" : [ {
    "product_name" : "Red Hat Enterprise Linux 10",
    "fix_state" : "Not affected",
    "package_name" : "varnish",
    "cpe" : "cpe:/o:redhat:enterprise_linux:10"
  }, {
    "product_name" : "Red Hat Enterprise Linux 8",
    "fix_state" : "Not affected",
    "package_name" : "varnish:6/varnish",
    "cpe" : "cpe:/o:redhat:enterprise_linux:8"
  }, {
    "product_name" : "Red Hat Enterprise Linux 9",
    "fix_state" : "Not affected",
    "package_name" : "varnish",
    "cpe" : "cpe:/o:redhat:enterprise_linux:9"
  } ],
  "references" : [ "https://www.cve.org/CVERecord?id=CVE-2026-40396\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-40396\nhttps://github.com/varnish/varnish/issues/15\nhttps://github.com/varnish/varnish/releases/tag/varnish-9.0.1" ],
  "name" : "CVE-2026-40396",
  "csaw" : false
}