{
    "CVE_data_meta": {
        "ASSIGNER": "cve@mitre.org",
        "ID": "CVE-2020-25603",
        "STATE": "PUBLIC"
    },
    "affects": {
        "vendor": {
            "vendor_data": [
                {
                    "product": {
                        "product_data": [
                            {
                                "product_name": "n/a",
                                "version": {
                                    "version_data": [
                                        {
                                            "version_value": "n/a"
                                        }
                                    ]
                                }
                            }
                        ]
                    },
                    "vendor_name": "n/a"
                }
            ]
        }
    },
    "data_format": "MITRE",
    "data_type": "CVE",
    "data_version": "4.0",
    "description": {
        "description_data": [
            {
                "lang": "eng",
                "value": "An issue was discovered in Xen through 4.14.x. There are missing memory barriers when accessing/allocating an event channel. Event channels control structures can be accessed lockless as long as the port is considered to be valid. Such a sequence is missing an appropriate memory barrier (e.g., smp_*mb()) to prevent both the compiler and CPU from re-ordering access. A malicious guest may be able to cause a hypervisor crash resulting in a Denial of Service (DoS). Information leak and privilege escalation cannot be excluded. Systems running all versions of Xen are affected. Whether a system is vulnerable will depend on the CPU and compiler used to build Xen. For all systems, the presence and the scope of the vulnerability depend on the precise re-ordering performed by the compiler used to build Xen. We have not been able to survey compilers; consequently we cannot say which compiler(s) might produce vulnerable code (with which code generation options). GCC documentation clearly suggests that re-ordering is possible. Arm systems will also be vulnerable if the CPU is able to re-order memory access. Please consult your CPU vendor. x86 systems are only vulnerable if a compiler performs re-ordering."
            }
        ]
    },
    "problemtype": {
        "problemtype_data": [
            {
                "description": [
                    {
                        "lang": "eng",
                        "value": "n/a"
                    }
                ]
            }
        ]
    },
    "references": {
        "reference_data": [
            {
                "url": "https://xenbits.xen.org/xsa/advisory-340.html",
                "refsource": "MISC",
                "name": "https://xenbits.xen.org/xsa/advisory-340.html"
            },
            {
                "refsource": "FEDORA",
                "name": "FEDORA-2020-306b84fd07",
                "url": "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/4JRXMKEMQRQYWYEPHVBIWUEAVQ3LU4FN/"
            },
            {
                "refsource": "FEDORA",
                "name": "FEDORA-2020-f668e579be",
                "url": "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/DA633Y3G5KX7MKRN4PFEGM3IVTJMBEOM/"
            },
            {
                "refsource": "DEBIAN",
                "name": "DSA-4769",
                "url": "https://www.debian.org/security/2020/dsa-4769"
            },
            {
                "refsource": "SUSE",
                "name": "openSUSE-SU-2020:1608",
                "url": "http://lists.opensuse.org/opensuse-security-announce/2020-10/msg00008.html"
            },
            {
                "refsource": "FEDORA",
                "name": "FEDORA-2020-d46fe34349",
                "url": "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/RJZERRBJN6E6STDCHT4JHP4MI6TKBCJE/"
            },
            {
                "refsource": "GENTOO",
                "name": "GLSA-202011-06",
                "url": "https://security.gentoo.org/glsa/202011-06"
            }
        ]
    }
}