{
  "schema_version": "1.4.0",
  "id": "GHSA-5wwp-3576-jfjc",
  "modified": "2022-05-24T17:14:11Z",
  "published": "2022-05-24T17:14:11Z",
  "aliases": [
    "CVE-2020-11739"
  ],
  "details": "An issue was discovered in Xen through 4.13.x, allowing guest OS users to cause a denial of service or possibly gain privileges because of missing memory barriers in read-write unlock paths. The read-write unlock paths don't contain a memory barrier. On Arm, this means a processor is allowed to re-order the memory access with the preceding ones. In other words, the unlock may be seen by another processor before all the memory accesses within the \"critical\" section. As a consequence, it may be possible to have a writer executing a critical section at the same time as readers or another writer. In other words, many of the assumptions (e.g., a variable cannot be modified after a check) in the critical sections are not safe anymore. The read-write locks are used in hypercalls (such as grant-table ones), so a malicious guest could exploit the race. For instance, there is a small window where Xen can leak memory if XENMAPSPACE_grant_table is used concurrently. A malicious guest may be able to leak memory, or cause a hypervisor crash resulting in a Denial of Service (DoS). Information leak and privilege escalation cannot be excluded.",
  "severity": [
    {
      "type": "CVSS_V3",
      "score": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H"
    }
  ],
  "affected": [],
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2020-11739"
    },
    {
      "type": "WEB",
      "url": "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/5M2XRNCHOGGTJQBZQJ7DCV6ZNAKN3LE2"
    },
    {
      "type": "WEB",
      "url": "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/NVTP4OYHCTRU3ONFJOFJQVNDFB25KLLG"
    },
    {
      "type": "WEB",
      "url": "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/YMAW7D2MP6RE4BFI5BZWOBBWGY3VSOFN"
    },
    {
      "type": "WEB",
      "url": "https://security.gentoo.org/glsa/202005-08"
    },
    {
      "type": "WEB",
      "url": "https://www.debian.org/security/2020/dsa-4723"
    },
    {
      "type": "WEB",
      "url": "https://xenbits.xen.org/xsa/advisory-314.html"
    },
    {
      "type": "WEB",
      "url": "http://lists.opensuse.org/opensuse-security-announce/2020-05/msg00006.html"
    },
    {
      "type": "WEB",
      "url": "http://www.openwall.com/lists/oss-security/2020/04/14/2"
    },
    {
      "type": "WEB",
      "url": "http://xenbits.xen.org/xsa/advisory-314.html"
    }
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-119",
      "CWE-362"
    ],
    "severity": "MODERATE",
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2020-04-14T13:15:00Z"
  }
}